C Primer Plus (第六版) 第十四章_编程练习答案
2024-04-20 23:36:43
no1.c
//重新编写复习题5,用月份名的拼写代替月份号(别忘了用strcmp()).在一个简单的程序中测试该函数
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
# include <ctype.h># define LEN 20struct month
{char name[20] ; char abbrev[4] ;int days ; int monumb ;
};long days(const struct month * months , int n , char * st);
char * s_get(char * st , int n);int main(void)
{char st[LEN] ;struct month months[12] = {"January" , "jan" , 31 , 1 ,"February" , "feb" , 28 , 2 ,"March" , "mar" , 31 , 3 ,"April" , "apr" , 30 , 4 ,"May" , "may" , 31 , 5 ,"June" , "jun" , 30 , 6 ,"July" , "jul" , 31 , 7 ,"August" , "aug" , 31 , 8 ,"September" , "sep" , 30 , 9 , "October" , "oct" , 31 , 10 ,"November" , "nov" , 30 , 11 ,"December" , "dec" , 31 , 12 ,};int n = 0 ;puts("Enter a number(empty line to quit) :");while (s_get(st , LEN)&& st[0] != '\0'){printf("total days is %ld\n" , days(months ,12 , st)); puts("Enter a number(empty line to quit) :");}/*打印所有结构体内容for (int i = 0 ; i < 12 ; i++){printf("No.%d\nmonth:%s\nabbrev:%s\ndays:%d\n",months[i].monumb,months[i].name ,months[i].abbrev,months[i].monumb);}*/return 0 ;
}long days(const struct month * months , int n , char * st)
{long ret_val = 0 ;char * p_month ;char * p_str ;int find = 0 ;// 我这里使用了比较麻烦的模糊查找// 考虑的比较多,考虑到了用户输入不全的问题// 你们可以用题目提示的strcmp函数精确查找// 缺陷是只要一个字符不对,就认为不是for (int i = 0 ; i < n ; i++){//动态分配空间,足够储存字符串p_month = (char *)calloc(sizeof(char) , strlen(months[i].name) + 1);p_str = (char *)calloc(sizeof(char) , strlen(st) + 1);//全部转换为小写for (int j = 0 ; j < sizeof(p_month); j++)p_month[j] = tolower(months[i].name[j]) ;for (int j = 0 ; j < sizeof(p_str); j++)p_str[j] = tolower(st[j]);//字符串中寻找用户输入的字符串,找到后退出循环if (strstr(p_month , p_str)){find = i + 1 ;break ;}}if (find){for (int i = 0 ; i < find ; i++)ret_val += months[i].days ;}return ret_val ;
}char * s_get(char * st , int n)
{char * ret_val ;char * find ;if (ret_val = fgets(st , n , stdin)){if (find = strchr(st , '\n'))*find = '\0' ;else while (getchar() != '\n');}return ret_val ;
}
no2.c
//编写一个函数,提示用户输入日月年,月份可以是月份号,月份拼写,或月份名,
//然后该程序返回一年中到用户指定日子的总天数(包含这一天)
# include <stdio.h>
# include <string.h>
# include <ctype.h>static struct
{char number[10] ; //月份号 按字符来char name[10]; //月份名char abb[10] ; //月份缩写int days ; //天数
}months[12] =
{"1" , "january" , "jan" , 31 ,"2" , "february" ,"feb" , 28 ,"3" , "march" , "mar" ,31 ,"4" , "april" , "apr" ,30 ,"5" , "may" , "may" , 31 ,"6" , "june" , "jun" ,30 ,"7" , "july" , "jul" ,31 ,"8" , "august" , "aug" ,31 ,"9" , "september" , "sep" ,30 ,"10" , "october" , "oct" ,31 ,"11" , "novbemer" , "nov" ,30 ,"12" , "december" , "dec" ,31 ,
};static struct
{int isleap ;int year ;int month ;int day;
}date;void get_year(void);
void get_month(void);
void get_day(void);
int total_day(void);int main(void)
{int days ;char ch ;do{get_year();get_month();get_day();days = total_day();printf("%d年到第%d月%d日一共是%d天\n" , date.year , date.month , date.day , days);puts("继续吗?(y/n):");scanf("%c" ,&ch);}while (tolower(ch) == 'y');return 0 ;
}void get_year(void)
{int y ; puts("请输入年份:");while (scanf("%d" , &y) != 1 || y < 0){while (getchar() != '\n') ;puts("输入错误,重新输入年份.");}while (getchar() != '\n') ;if (y % 4 == 0)if (y % 100 == 0 && y % 400 != 0)date.isleap = 0 ;elsedate.isleap = 1 ;else date.isleap = 0 ;date.year = y ;
}void get_month(void)
{char m[100] ;char * find ;int i = 0 ; do{puts("请输入月份:");if (fgets(m , 100 , stdin)) //这里将\n也读进来了{if (find = strchr(m , '\n')) //如果是完整的一行,就将读入的\n处理为\0*find = '\0' ;else while (getchar() != '\n') ; //如果读入的是不完整的一行,将剩下的内容清理掉}for (i = 0 ; i < 12 ; i++){if (strcasecmp(months[i].number , m) == 0 || strcasecmp(months[i].name , m) == 0 ||strcasecmp(months[i].abb , m) == 0){date.month = i + 1 ;break ;}}if (i >= 12){while (getchar() != '\n') ;printf("输入错误,");}}while (i >= 12) ;//while (getchar() != '\n') ; //<----如果有行,会出现再次输入的情况,原因是:前面的sgets已经将一行中剩下的清理了// 这里本意为清理剩余输出,就变成了等待输入了.属于逻辑有错误
}void get_day(void)
{int d ;int vaild = 0 ;while (!vaild){puts("请输入日子:");while (scanf("%d" , &d) != 1){while (getchar() != '\n') ;puts("输入错误,清重新输入日子");}// months[month - 1].days + (isleap && month == 2)// 0 0 0 不是闰年 , 不是2月份// 0 1 0 不是闰年 , 是2月份// 1 0 0 是闰年, 不是2月份// 1 1 1 是闰年, 是2月份//if (d > (date.isleap && date.month == 2) + months[date.month - 1].days || d < 1){puts("无效日期,请重新输入");}else vaild = 1 ;}date.day = d ;while (getchar() != '\n') ;
}int total_day(void)
{int days = 0;for (int i = 0 ; i < date.month - 1 ; i++){days += months[i].days ;}days += date.day ;if (date.isleap && date.month > 2)days++ ;return days ;
}
no3.c
//修改程序清单14.2中的图书目录程序,使其按照输入图书的顺序输出图书的的信息,
//然后按照标题的字母的声明输出信息,最后按照价格的升序输出图书的信息
# include <stdio.h>
# include <string.h># define MAXTITL 40
# define MAXAUTL 40
# define MAXBKS 100char * s_gets(char * st , int n);struct book
{char title[MAXTITL] ; //书名char author[MAXAUTL] ; //作者float value ; //价格
};int main(void)
{struct book library[MAXBKS] ;int count = 0 ; int index ; printf("Please enter the book title .\n");printf("Press [enter] at the start of line to stop .\n");while (count < MAXBKS && s_gets(library[count].title , MAXTITL) != NULL&& library[count].title[0] != '\0'){printf("Now enter the author.\n");s_gets(library[count].author , MAXAUTL);printf("Now enter the value.\n");scanf("%f" , &library[count++].value);while (getchar() != '\n') ;if (count < MAXBKS)printf("Enter the next title . \n");}if (count > 0){printf("Here is the list of your books:\n");for (index = 0 ; index < count ; index++)printf("%s by %s : $%.2f\n" , library[index].title , library[index].author,library[index].value);//-------------------------------↓添加以下代码//按字符声明顺序(选择排序)for (int i = 0 , j = 0 ; i < count - 1 ; i++){int min_index = i;for (j = i + 1 ; j < count ; j++)if (strcmp(library[min_index].title , library[j].title) > 0)min_index = j ;struct book tmp_book = library[i] ;library[i] = library[min_index] ;library[min_index] = tmp_book ;}puts("\n按字符声明排序如下");for (index = 0 ; index < count ; index++)printf("%s by %s : $%.2f\n" , library[index].title , library[index].author,library[index].value);//按价格顺序(冒泡排序)for (int i = 0 ; i < count - 1 ; i++){for (int j = 0 ; j < count - 1 - i ; j++){if (library[j].value > library[j + 1].value){struct book tmp_book = library[j];library[j] = library[j + 1] ;library[j + 1] = tmp_book ;}}}puts("\n按价格.排序如下");for (index = 0 ; index < count ; index++)printf("%s by %s : $%.2f\n" , library[index].title , library[index].author,library[index].value);//-------------------------------↑}elseprintf("No books? Too bad.\n");return 0 ;
}char * s_gets(char * st , int n)
{char * ret_val ;char * find ;ret_val = fgets(st , n , stdin);if (ret_val){find = strchr(st , '\n');if (find)*find = '\0' ;elsewhile (getchar() != '\n') ;}return ret_val ;
}
no4.c
//编写一个程序,创建一个有两个成员的结构模板
//a. 第1个成员是社会保险号,第2个成员是一个有3个成员的结构,第1个成员代表名,第2个成员代表中间名,第3个成员代表姓.
// 创建并初始化一个内含5个该类型结构的数组.该程序以下面的格式打印数据:
// Dribble , Flossie M. -- 302039823
//b. 修改a部分,传递结构的值而不是结构的地址.# include <stdio.h># define LEN 20struct person
{unsigned long long id ;struct {char fname[LEN] ;char mname[LEN] ;char lname[LEN] ;};
};void a_print(const struct person * pstc , int n);
void b_print(struct person ps);int main(void)
{struct person shebao[5] = {2374856963 , "yuan" , "li" , "D" ,2374856964 , "meng" , "qi" , "D" ,2374856965 , "zhu" , "ge" , "liang" , 2374856966 , "xia" , "hou" , "dun" ,2374856967 , "si" , "ma" , "gang"};printf("Part_A:\n"); printf("--------------------------\n");a_print(shebao , 5);printf("\nPart_B:\n");printf("--------------------------\n");for (int i = 0 ; i < 5 ; i++)b_print(shebao[i]);return 0 ;
}void a_print(const struct person * pstc , int n)
{for (int i = 0 ; i < n ; i++ , pstc++){printf("%s , %s %s.\t -- %llu\n",pstc->fname , pstc->lname , pstc->mname , pstc->id);}
}void b_print(struct person ps)
{printf("%s , %s %s.\t -- %llu\n" , ps.fname , ps.lname ,ps.mname , ps.id);
}
no5.c
//编写一个程序满足以下的要求.
//a. 外部定义一个有两个成员的结构模板 name :一个字符串储存名 , 一个字符串储存姓;
//b. 外部定义一个有3个成员的结构模板 student:一个name类型的结构,一个grade数组
// 储存3个浮点型分数,一个变量储存3个分数平均数.
//c. 在main()函数中声明一个内含CSIZE(CSIZE = 4)个student类型结构的数组,并初始化
// 这些结构的名字部分.用函数g,e,f和g中描述任务.
//d. 以交互的方式获取每个学生的成绩,提示用户输入学生的姓名和分数.把分数储存到
// grade数组相应的结构中.可以在main()函数或其他函数中循环来完成
//e. 计算每个结构的平均分 , 并把计算后的值赋给合适的成员.
//f. 打印每个结构的信息.
//g. 打印班级的平均分,即所有结构的数值成员的平均值.# include <stdio.h># define LEN 10
# define CSIZE 4struct name
{char sname[LEN] ;char name[LEN] ;
};struct student
{struct name st_name;float grade[3] ;float average ;
};void in_score(struct student * pstr);
float get_float(void);
void out_score(const struct student * pstr , int n);int main(void)
{struct student stu[CSIZE] = {[0].st_name.sname = "zhang" , "san" ,[1].st_name.sname = "li" , "si" ,[2].st_name.sname = "wang" ,"wu" ,[3].st_name.sname = "zhao" , "liu"};for (int i = 0 ; i < CSIZE ; i++)in_score(&stu[i]) ;out_score(stu , CSIZE);
}void in_score(struct student * pstr)
{static char * lession[] = {"语文" , "数学" ,"英语" };float sum = 0 ;int i ;for (i = 0 ; i < 3 ; i++){printf("请输入%s %s的%s成绩:" , pstr->st_name.sname ,pstr->st_name.name , lession[i]);pstr->grade[i] = get_float() ;sum += pstr->grade[i] ;}pstr->average = sum / i ;
}float get_float(void)
{float f = 0 ;while (scanf("%f" , &f) != 1 || f < 0 || f > 100){while (getchar() != '\n') ;puts("无效输入,请重新输入");}return f ;
}void out_score(const struct student * pstr , int n)
{float sum = 0 ;printf("%10s %-10s %10s %10s %10s %10s \n" ,"姓" ,"名" , "语文" , "数学" , "英语" , "平均");for (int i = 0 ; i < n ; i++){printf("%10s %-10s %10.1f %10.1f %10.1f %10.1f\n" ,pstr[i].st_name.sname , pstr[i].st_name.name ,pstr[i].grade[0] , pstr[i].grade[1] , pstr[i].grade[2],pstr[i].average) ;sum += pstr[i].average ;}printf("全班的平均成绩是:%.1f\n" , sum / n);
}
no6.c
//一个文本文件中保存着一个垒球队的信息.每行数据都是这样排列的: 4 Jessie Joybat 5 2 1 1
//第1项是球员号,为了方便起见,其范围是0-18.第2项是球员的名.第3项是球员的姓.名和姓,都是一个单词
//第4项是官方统计的球员上场次数.接着3项分别是击中数,走垒数和打点(RBI).文件可能包含多场比赛的
//数据.编写一个程序,把数据储存到一个结构数组中.该结构中的成员要分别表示球员名,姓,上场次数,击中
//数,走垒数,打点和安打率(稍后计算).可以使用球员号作为数组索引.该程序要读到文件结尾.并统计每一位
//球员的各项累计总和.
//世界棒球统计与之相关.例如,一次走垒和触垒中的失误不计入上场次数,但是可能产生一个RBI.但是该程序
//要做的是像下面描述的一样读取和处理数据文件,不会关心数据的实际含义.要实现这些功能,最简单的方法是
//把结构的内容都初始化为0,把文件中的数据读入临时变量中,然后将其加入相应的结构中,程序读完文件后,应
//计算每一位球员的安打率,并把计算结果储存到结构的相应成员中.计算安打率是用球员的累计击中数除以上
//场次数.这是一个浮点数计算.最后程序结合整个球队的统计数据,一行显示一位球员的累计数据.# include <stdio.h>
# include <stdlib.h># define LEN 10typedef struct
{int num ; //球员号char fname[LEN] ; //名char lname[LEN] ; //姓int play_times ; //上场次数int hit_times ; //击中次数int walk_times ; //走垒数int rbi ; //打点float hit_rate ; //安打率
}player;int main(void)
{FILE * fp ;player * pstr ;player tmp_player ;int count = 0 ;int flag = 0 ;//打开文件if ((fp = fopen("no2.txt" , "r")) == NULL){puts("打开文件失败");exit(EXIT_FAILURE);}while (fscanf(fp , "%d %s %s %d %d %d %d\n" , &tmp_player.num ,tmp_player.fname , tmp_player.lname ,&tmp_player.play_times , &tmp_player.hit_times,&tmp_player.walk_times , &tmp_player.rbi) != EOF){flag = 0 ;//先找此队员for (int i = 0 ; i < count ; i++){if (pstr[i].num == tmp_player.num){flag = 1 ;pstr[i].play_times += tmp_player.play_times ;pstr[i].hit_times += tmp_player.hit_times ;pstr[i].walk_times += tmp_player.walk_times ;pstr[i].rbi += tmp_player.rbi ;pstr[i].hit_rate = (double)pstr[i].hit_times / (double)pstr[i].play_times ;}}//未找到,添加新队员的信息if (!flag){if (count == 0)pstr = (player *)malloc(sizeof(player) * ++count); elsepstr = (player *)realloc(pstr , sizeof(player) * ++count);pstr[count - 1] = tmp_player ;pstr[count - 1].hit_rate = (double)pstr[count - 1].hit_times / (double)pstr[count - 1].play_times ; }}//打印每个球员的统计结果for (int i = 0 ; i < count ; i++){printf("%-10d %-10s %-10d %-10d %-10d %-10d %-10.d %10.2f%%\n" , pstr[i].num ,pstr[i].fname ,pstr[i].lname ,pstr[i].play_times ,pstr[i].hit_times ,pstr[i].walk_times ,pstr[i].rbi ,pstr[i].hit_rate);}fclose(fp); //关闭文件free(pstr); //释放空间return 0 ;
}
no7.c
//修改程序清单14.14,从文件中读取每条记录并显示出来,允许用户删除记录或者修改记录内容.
//如果删除记录,把空出来的空间留给下一个要读入的记录.要修改现有的文件内容,必须用"r+b"
//模式,而且,必需更加注意定位文件指针,防止新加入的记录覆盖现有记录.最简单的方法是改动
//在内存中的所有数据,然后再把最后的信息写入文件.跟踪的一个方法是在book结构中添加一个
//成员表示是否该项目删除.
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# include <ctype.h>
# include <math.h>
# include <windows.h># define MAXTITL 40
# define MAXAUTL 40
# define MAXBKS 10struct book
{int del_flag;char title[MAXTITL] ;char author[MAXAUTL] ;float value ;
};char * s_gets(char * st , int n) ;
FILE * file_open(const char * st) ;
long fdisplay(FILE * fp);
int menu_choice(FILE * fp);
void out_menu(void);
int fappend(FILE * fp);
int fmodify(FILE * fp);
int fdelete(FILE * fp);
int refresh(FILE * fp);int main(void)
{struct book library[MAXBKS] ;int count = 0 ;int index , filecount ; FILE * pbooks ;int size = sizeof(struct book);/*将编程清单14.14中这一段独立为 file_open();//打开文件if ((pbooks = fopen("book.dat" , "a + b")) == NULL){fputs("Can't open book.dat file\n" , stderr);exit(EXIT_FAILURE);}*//* 将编程清单中14.14中这一段独立为 fdisplay()函数rewind(pbooks);while (count < MAXBKS && fread(&library[count] , size , 1 , pbooks) == 1){if (count == 0)puts("Current contents of book.dat:");printf("%s by %s : $%.2f\n" , library[count].title , library[count].author ,library[count].value);count++ ;}filecount = count ;*/pbooks = file_open("r + b");while (menu_choice(pbooks)) ;/* 将程序清单14.14这一段独立为fappend()函数puts("Please add new book titles.");puts("Press [enter] at the start of a line to stop.");while (count < MAXBKS && s_gets(library[count].title , MAXTITL) != NULL&& library[count].title[0] != '\0'){puts("Now enter the author.");s_gets(library[count].author , MAXAUTL);puts("Now enter the value.");scanf("%f" , &library[count++].value);while (getchar() != '\n') ;if (count < MAXBKS)puts("Enter the next title.");}if (count > 0){puts("Here is the list of your books:");for (index = 0 ; index < count ; index++)printf("%s by %s : $%.2f\n" , library[index].title ,library[index].author , library[index].value);fwrite(&library[filecount] , size , count - filecount , pbooks);}elseputs("No books? Too bad.\n");*/puts("Bye.\n");fclose(pbooks);return 0 ;
}char * s_gets(char * st , int n)
{char * ret_val = NULL ;char * find ;if (ret_val = fgets(st , n , stdin)){if (find = strchr(st , '\n'))*find = '\0' ;elsewhile (getchar() != '\n') ;}return ret_val ;
}FILE * file_open(const char * st)
{FILE * fp ;if ((fp = fopen("book.dat" , st)) == NULL) //如果打开失败{if ((fp = fopen("book.dat" , "w+b")) == NULL) //新建文件{fputs("打开文件失败\n" , stderr);exit(EXIT_FAILURE);}fclose(fp);if ((fp = fopen("book.dat" , "r+b")) == NULL) //重新以读写方式打开{fputs("打开文件失败\n" , stderr);exit(EXIT_FAILURE);}}return fp ;
}int menu_choice(FILE * fp)
{int choice ;out_menu();for (int i = 0 ; !scanf("%d", &choice); i++){while (getchar() != '\n') ;puts("非法输入,请输入正确的选项");if ((i + 1) % 5 == 0)out_menu() ;}while (getchar() != '\n') ;switch (choice){case 1:fdisplay(fp);break ;case 2://修改fmodify(fp);break ;case 3://添加fappend(fp);break ;case 4://删除fdelete(fp);system("pause");break;case 5: //退出文件操作//退出操作,将刷新文本,所有删除操作都将生效refresh(fp);choice = 0 ;break ;default ://出错choice = -1 ;puts("无效选择");system("pause");break;}return choice ;
}void out_menu(void)
{ static char * menu[] = {"#################################","请选择您需要的操作:" ,"1) 查看 2)修改","3) 添加 4)删除","5) 退出" , "#################################"};system("cls");for(int i = 0 ; i < sizeof(menu) / sizeof(menu[0]) ; i++)puts(menu[i]);
}long fdisplay(FILE * fp)
{long count = 0 ;struct book tmp_book ;puts("==========================================");rewind(fp);while (fread(&tmp_book , sizeof(struct book), 1 , fp)){if (!tmp_book.del_flag){printf("%s by %s : $%.2f\n" , tmp_book.title ,tmp_book.author , tmp_book.value);count++ ;}}rewind(fp);puts("==========================================");system("pause");return count ;
}int fappend(FILE * fp)
{int state = 0 ;struct book tmp ;puts("请输入您要添加的书名:");puts("按[Enter]输入空行退出:");while (s_gets(tmp.title , MAXTITL) && tmp.title[0]){puts("请输入作者:");while (!s_gets(tmp.author , MAXAUTL))puts("输入非法,请重新输入作者");puts("请输入价格:");while (!scanf("%f" , &tmp.value) || tmp.value < 0){while (getchar() != '\n') ;puts("无效数值,请重新输入");}while (getchar() != '\n') ;tmp.del_flag = 0 ; //初始化删除标志位为0 , 表示未删除fseek(fp , 0L , SEEK_END); //文件指针定位到文件最后state = fwrite(&tmp , sizeof(struct book), 1 , fp);fflush(fp);puts("请输入下一本书名:");}rewind(fp);return state ;
}int fmodify(FILE * fp)
{const char * tip = "无需修改请按[Enter]输入空行进入下一项";int state = 0 ;struct book tmp ;char bookname[MAXTITL];char tmp_st[MAXTITL] ; float tmp_flt = 0 ; //得到用户想要修改的 书名 并找到指定书名 未找到则回复用户未找到 puts("请输入您想要修改的书名:");s_gets(bookname , MAXTITL);rewind(fp);while (state = fread(&tmp , sizeof(struct book) , 1 , fp)){if (strcmp(tmp.title , bookname) == 0)break ;}if (state){state = 0 ; //初始化状态值;puts("===============================");printf("%s\n请输入新的书名,%s\n",tmp.title , tip);while (!s_gets(tmp_st ,MAXTITL))puts("非法输入");if (*tmp_st && strcmp(tmp.title , tmp_st) != 0)strcpy(tmp.title , tmp_st);strcpy(tmp_st , "");puts("===============================");printf("%s\n请输入新的作者,%s\n",tmp.author , tip);while (!s_gets(tmp_st , MAXTITL))puts("非法输入");if (*tmp_st && strcmp(tmp.author , tmp_st) != 0)strcpy(tmp.author , tmp_st);strcpy(tmp_st , "") ;puts("===============================");printf("$%.2f\n请输入新的价格,%s\n" , tmp.value , tip);while (!s_gets(tmp_st , MAXTITL) || (tmp_flt = atof(tmp_st)) < 0) printf("无效输入");if (tmp_flt > 0)tmp.value = tmp_flt ;strcpy(tmp_st , "");tmp.del_flag = 0 ; //初始化删除标志位为0 ,表示未删除puts("===============================");printf("将修改为:\n书名:%s\n作者:%s\n价格:%.2f\n " , tmp.title , tmp.author , tmp.value);puts("-------------------------------");puts("确定修改吗?(y/n)");if (s_gets(tmp_st , MAXTITL) && tolower(tmp_st[0]) == 'y'){fseek(fp , -((long)sizeof(struct book)) , SEEK_CUR);state = fwrite(&tmp , sizeof(struct book) , 1 , fp);fflush(fp);}if (state){puts("===============================");puts("修改成功!\n任意键返回菜单页面");getchar();}}else {puts("===============================");puts("书名不存在,请检查输入.\n任意键返回菜单页面");getchar();}rewind(fp);return state ;
}int fdelete(FILE * fp)
{int state = 0 ;struct book tmp ;char tmp_st[MAXTITL] ;int find = 0 ;int count = 0;// 判断文件是否有内容 , 无内容则不能修改fseek(fp , 0L , SEEK_END);if (ftell(fp) == 0){puts("错误:文件内无内容");return 0 ;}rewind(fp);puts("请输入您要删除的书名");if (s_gets(tmp_st , MAXTITL)){rewind(fp);while (find = fread(&tmp , sizeof(struct book) , 1 , fp)){if (strcmp(tmp.title , tmp_st) == 0) //如果找到了,就将删除标志位置1{tmp.del_flag = 1; //删除标志位置1fseek(fp , -((long)sizeof(struct book)) , SEEK_CUR); //定位到此记录fwrite(&tmp , sizeof(struct book) , 1 , fp); //覆盖此记录fflush(fp); //刷新文件break ;}}if (find)puts("删除成功,返回菜单页面");elseputs("未找到该书籍,请确认书名,或者添加该书籍");rewind(fp);}else {puts("无效输入");state = 0 ;} return state ;
}int refresh(FILE * fp)
{FILE * fp_tmp ;struct book bk_tmp ;int state = 0 ;if (!(fp_tmp = fopen("book.tmp" , "wb+"))){fputs("关闭文件失败" , stderr);exit(EXIT_FAILURE);}rewind(fp) ;while (fread(&bk_tmp , sizeof(struct book) , 1 , fp)){if (!bk_tmp.del_flag){if (!fwrite(&bk_tmp , sizeof(struct book) , 1 , fp_tmp)){fputs("写入文件失败" , stderr);exit(EXIT_FAILURE);}}}fclose(fp_tmp);fclose(fp);system("del book.dat");system("rename book.tmp book.dat");return state ;
}//由于no7.c代码结构混乱,语句冗长,可读性,与维护性较低,所以最终决定重构no7.c
//以下程序思路,基于内存操作,使用了函数指针等简洁,可读性,维护性较高的技巧
//执行原理,程序启动将读取指定文件内所有内容,将内容整个放在内存中,关闭文件.
//接下来的增删查改等操作都对内存操作,当程序结束时,将内存中的所有数据重新写入
//文件内.
//缺点是对内存开销较大...但是目前我还未想到更好的办法
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# include <windows.h># define MAXTITL 20 //最大书名长度
# define MAXAUTL 20 //最大作者名长度
# define FILENAME "book.dat" //宏定义文件名
# define FLDWIDTH 15 //字段宽度(表格)// 声明书籍结构体
typedef struct
{char title[MAXTITL] ;char author[MAXAUTL] ;float value ;
}book;//定义全局结构体
static struct
{long COUNT ;book * BOOKS ;
}LIBRARY;long load_file(char * file);
long refresh_file(char * file);
void print_hline(const char ch , int count);
void print_squared(const char * st , int fwidth);
char * s_gets(char * st , int n);void out_menu(void);
int menu_choice(void);
void menu_end(void);
void lib_out(void); //查
void lib_modify(void); //改
void lib_add(void); //增
void lib_del(void); //删
int abort_operation(); //放弃操作int main(void)
{char ch[20] ;load_file(FILENAME) ;system("cls");while (menu_choice()){system("pause");system("cls");}refresh_file(FILENAME);free(LIBRARY.BOOKS);return 0 ;
}long load_file(char * file)
{FILE * fp ;long size = 0;long item = 0 ;if (!(fp = fopen(file , "rb"))) //打开文件失败{if (!(fp = fopen(file , "wb"))) //创建新的文件{fputs("创建文件失败" , stderr);exit(1);}fclose(fp);if (!(fp = fopen(file , "rb"))) //关闭文件并以读方式重新打开{fputs("打开文件失败" , stderr);exit(1);}}fseek(fp , 0L , SEEK_END); size = ftell(fp);LIBRARY.COUNT = size / sizeof(book) ;LIBRARY.BOOKS = (book *) calloc(LIBRARY.COUNT , sizeof(book)) ; //分配内存rewind(fp); //文件指针重新定位到文件首item = fread(LIBRARY.BOOKS , sizeof(book) , LIBRARY.COUNT , fp);//读取文件fclose(fp);return item ;
}long refresh_file(char * file)
{FILE * fp ;long item = 0 ;if (!(fp = fopen(file , "wb"))){fputs("更新文件失败" , stderr);exit(2);}item = fwrite(LIBRARY.BOOKS , sizeof(book) , LIBRARY.COUNT , fp);fclose(fp);return item ;
}void print_squared(const char * st , int fwidth)
{printf("%-*c%s%*c" , (fwidth - strlen(st)) / 2 , '|' , st , (fwidth - strlen(st)) / 2 , '|');
}void print_hline(const char ch , int count)
{putchar(' ');while (--count)putchar(ch);putchar('\n');
}char * s_gets(char * st , int n)
{char * find ;if (fgets(st , n , stdin)){if (find = strchr(st , '\n'))*find = '\0' ;else while (getchar() != '\n') ;}return st ;
}int menu_choice(void)
{static const void (* menu[])(void) = {menu_end , lib_out , lib_modify , lib_add , lib_del};int cmd = 0 ;out_menu();while (!scanf(" %d" , &cmd) || cmd < 0 || cmd > 4){if ((cmd < 0) || (cmd > 4))fputs("无效选择,请输入正确的序号:\n" , stderr);elsefputs("非法输入\n" , stderr);while (getchar() != '\n') ;}while (getchar() != '\n') ;menu[cmd]();return cmd ;
}void out_menu(void)
{ static char * menu[] = {"#################################","请选择您需要的操作:" ,"1) 查看 2) 修改","3) 添加 4) 删除","0) 退出" , "#################################"};for(int i = 0 ; i < sizeof(menu) / sizeof(menu[0]) ; i++)puts(menu[i]);
}
void menu_end(void)
{puts("再见,祝您生活愉快!");
}void lib_out(void)
{static const char * label[] = {"书名" ,"作者" ,"价格"} ;char tmp[100] ;// 打印表头print_hline('=' , (sizeof(label) / sizeof(label[0])) * FLDWIDTH - 4);for (int i = 0 ; i < sizeof(label) / sizeof(label[0]) ; i++)print_squared(label[i] , FLDWIDTH);putchar('\n');print_hline('=' , (sizeof(label) / sizeof(label[0])) * FLDWIDTH - 4);// 打印数据for (int i = 0 ; i < LIBRARY.COUNT; i++){print_squared(LIBRARY.BOOKS[i].title , FLDWIDTH);print_squared(LIBRARY.BOOKS[i].author , FLDWIDTH);sprintf(tmp ,"%.1f" ,LIBRARY.BOOKS[i].value) ;print_squared(tmp , FLDWIDTH);putchar('\n');print_hline('-' , (sizeof(label) / sizeof(label[0])) * FLDWIDTH - 4);}
}void lib_modify(void)
{book tbook ;char tstr[100] ;char answer ;int i ;float tfloat = 0 ;if (!LIBRARY.COUNT){puts("书籍为空,不能修改");return ;}lib_out();puts("请输入您要修改的书名(输入空行退出):");while (s_gets(tstr , 100) && tstr[0]){for (i = 0 ; i < LIBRARY.COUNT ; i++)if (strcmp(LIBRARY.BOOKS[i].title , tstr) == 0)break; if (i > LIBRARY.COUNT - 1) //未找到书名给出提示puts("您输入的书名不存在!");else {tbook = LIBRARY.BOOKS[i] ;printf("书名: %s\n无需修改请按[Enter]输入空行\n" , tbook.title);if (s_gets(tstr , 100) && tstr[0])strncpy(tbook.title , tstr , MAXTITL) ;printf("作者: %s\n无需修改请按[Enter]输入空行\n" , tbook.author);if (s_gets(tstr , 100) && tstr[0])strncpy(tbook.author , tstr , MAXAUTL);printf("价格: %.1f\n无需修改请按[Enter]输入空行\n" , tbook.value);while (!s_gets(tstr , 100) || !tstr[0] || (tfloat = atof(tstr)) <= 0){if (!tstr[0]){tfloat = tbook.value ;break ;}elseputs("输入价格无效,请重新输入");}tbook.value = tfloat ;puts("=============================================");printf("书名: %s\n作者: %s\n价格: %.1f\n" , tbook.title , tbook.author , tbook.value);puts("您确定要修改?(y/n)");if (scanf(" %c" , &answer) && 'y' == tolower(answer)){LIBRARY.BOOKS[i] = tbook ;puts("修改成功!");}while (getchar() != '\n') ;}puts("请输入您要修改的下一本书名(空行退出)");}
}void lib_add(void)
{book tbook = {.value = 0} ;char ch ;char tmp[100] ;float tfloat = 0 ;puts("请输入您要添加的书名(输入空行退出)");while (s_gets(tbook.title , MAXTITL) && !tbook.title[0])if (abort_operation())return ;elseputs("请输入您要添加的书名(输入空行退出)");puts("请输入该书的作者,或者出版社(输入空行退出)");while (s_gets(tbook.author , MAXAUTL) && !tbook.author[0])if (abort_operation())return ;elseputs("请输入该书的作者,或者出版社(输入空行退出)");puts("请输入该书的价格(输入空行退出)");while (!s_gets(tmp , 100) || !tmp[0] || (tfloat = atof(tmp)) <= 0){if (!tmp[0]){if (abort_operation())return ;elseputs("请输入该书的价格(输入空行退出)");}else puts("输入价格无效,请重新输入(输入空行退出)");}tbook.value = tfloat ;puts("================================");puts("以下是您要添加的书籍信息:");printf("书名: %s\n" , tbook.title);printf("作者: %s\n" , tbook.author);printf("价格: %.1f\n" , tbook.value);puts("确认添加吗?(y/n)");if(scanf(" %c" , &ch) && 'y' == tolower(ch)){/*if (!LIBRARY.COUNT)LIBRARY.BOOKS = (book *)calloc(++LIBRARY.COUNT , sizeof(book)) ;else*/LIBRARY.BOOKS = (book *)realloc(LIBRARY.BOOKS ,++LIBRARY.COUNT * sizeof(book)) ;LIBRARY.BOOKS[LIBRARY.COUNT - 1] = tbook ;}
}void lib_del(void)
{char tmp_title[MAXTITL] ;int i ;if (!LIBRARY.COUNT){puts("书籍为空,不能删除");return ;}lib_out();puts("请输入您要删除的书名(空行退出)");while (s_gets(tmp_title ,MAXTITL) && tmp_title[0]){//寻找相同的书名for (i = 0 ; i < LIBRARY.COUNT ; i++)if (strcmp(LIBRARY.BOOKS[i].title , tmp_title) == 0)break; if (i > LIBRARY.COUNT - 1) //未找到书名给出提示puts("您输入的书名不存在!");else {for (int j = i ; j < LIBRARY.COUNT ; j++)LIBRARY.BOOKS[j] = LIBRARY.BOOKS[j + 1] ;LIBRARY.BOOKS = (book *)realloc(LIBRARY.BOOKS , --LIBRARY.COUNT * sizeof(book));puts("删除成功!");}puts("请输入您要删除的书名(空行退出)");}
}int abort_operation()
{int answer = 0 ;char ch ;puts("你确定要放弃本次操作,并返回菜单页面?(y/n)");if (scanf(" %c" , &ch) && 'y' == tolower(ch))answer = 1 ;elseanswer = 0 ;while (getchar() != '\n');return answer ;
}no8.c
//巨人航空公司的机群由12个座位的飞机组成.它每天飞行一个航班.根据下面的要求,编写一个座位预定程序
//a. 该程序使用一个内含12个结构的数组.每个结构中包括:一个成员表示座位编号.一个成员表示座位是否
// 已经被预定,一个成员表示预定人名,一个成员表示预定人的姓.
//b. 该程序显示下面的菜单:
// To choose a function enter its letter label:
// a) Show number of empty seats
// b) Show list of emppty seats
// c) Show alphabetical list of seats
// d) Assign a customer to a seat assignment
// e) Delete a seat assignment
// f) Quit
//c. 该程序能成功执行上面给出的菜单.选择d)和e)要提示用户进行额外输入,每个选项都能让用户终止输入.
//d. 执行特定程序后,该程序再次显示菜单,除非用户选择f).# include <stdio.h>
# include <ctype.h>
# include <windows.h># define NAME_LEN 50
# define SEAT_COUNT 12typedef struct
{int number ;int selected ;char name[NAME_LEN] ;char s_name[NAME_LEN];
}seat;int initialize_seat(seat * pstr , int n);
void print_menu(void);
char choice_menu(void);
int switch_menu(int choice , seat * pstr);
int empty_seat_count(const seat * pstr , int n);
int show_seat_list(const seat * pstr , int n);
int sort_seat_list(seat * pstr , int n);
int choice_seat(seat * pstr , int n);
int delte_seat(seat * pstr , int n);
char * s_gets(char * st , int n);int main(void)
{seat plane_seat[SEAT_COUNT] ;initialize_seat(plane_seat , SEAT_COUNT); //初始化座位while (switch_menu(choice_menu() , plane_seat)) ;puts("Bye. See you next!");return 0 ;
}int initialize_seat(seat * pstr , int n)
{int i;for (i = 0 ; i < n ; i++){pstr[i].number = i + 1 ;pstr[i].selected = 0 ;pstr[i].name[0] = '\0' ;pstr[i].s_name[0] = '\0' ;}return (i == n ? i : 0) ;
}char choice_menu(void)
{char ch ;print_menu();while (!scanf(" %c" , &ch) || !isalpha(ch = tolower(ch))){while (getchar() != '\n') ;puts("输入非法,请重新输入");}while (getchar() != '\n') ;return ch ;
}void print_menu(void)
{static char * menu[] = {"To choose a function enter its letter label:","a) Show number of empty seats","b) Show list of empty seats","c) Show alphabetical list of seats","d) Assign a customer to a seat assignment","e) Delete a seat assignment","f) Quit"};system("cls");for (int i = 0 ; i < sizeof(menu) / sizeof(menu[0]) ; i++)puts(menu[i]);
}int switch_menu(int choice , seat * pstr)
{switch (choice){case 'a' ://显示未预定的座位数量empty_seat_count(pstr , SEAT_COUNT);system("pause");return 1;case 'b' ://显示空的座位列表show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'c' ://按字母顺序显示座位列表sort_seat_list(pstr , SEAT_COUNT) ;system("pause");return 1 ;case 'd' ://为客户分配座位choice_seat(pstr , SEAT_COUNT);system("cls");show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'e' ://删除座位分配delte_seat(pstr , SEAT_COUNT);system("cls");show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'f' ://退出return 0 ;default ://错误选择puts("无效选择,请重新选择");system("pause");return 1 ;}
}int empty_seat_count(const seat * pstr , int n)
{int count = 0 ;for (int i = 0 ; i < n ; i++){if (pstr[i].selected == 0)count++ ;}printf("现在空座为还剩%d个\n" , count);return count ;
}int show_seat_list(const seat * pstr , int n)
{int i ;puts("当前座位信息:");/*for (i = 0 ; i < n ; i++){if (pstr[i].selected == 0)printf("座位号: %2d (空)\n" , pstr[i].number);}*/for (i = 0 ; i < n ; i++)printf("座位号: %-5d %-5s 名:%-20s 姓:%-20s\n" ,pstr[i].number ,pstr[i].selected ? "已预订" : "未预定" ,pstr[i].name ,pstr[i].s_name );return i ;
}int sort_seat_list(seat * pstr , int n)
{seat ** pstr_arr ;seat * tmp ;int min ;pstr_arr = (seat **)calloc( n , sizeof(seat *));for (int i = 0 ; i < n ; i++)pstr_arr[i] = &pstr[i] ;for (int i = 0 ; i < n - 1; i++){/*for (int j = 0 ; j < n - 1 - i ; j++){if (strcmp(pstr_arr[j]->name , pstr_arr[j + 1]->name) < 0){tmp = pstr_arr[j] ;pstr_arr[j] = pstr_arr[j + 1] ;pstr_arr[j + 1] = tmp ;}}*////*min = i ;for (int j = i + 1 ; j < n ; j++) if (strcmp(pstr_arr[min]->name , pstr_arr[j]->name) > 0)min = j ;if (min != i){tmp = pstr_arr[i] ;pstr_arr[i] = pstr_arr[min] ;pstr_arr[min] = tmp ;}//*/}for (int i = 0 ; i < n ; i++)printf("座位号: %-5d %-5s 名:%-20s 姓:%-20s\n" ,pstr_arr[i]->number ,pstr_arr[i]->selected ? "已预订" : "未预定" ,pstr_arr[i]->name ,pstr_arr[i]->s_name );free(pstr_arr);}int choice_seat(seat * pstr , int n)
{seat tmp ;char ch ;int flag = 0;puts("请输入您要挑选的座位号:");while (!scanf(" %d" , &tmp.number) || tmp.number < 1 || tmp.number > n || (flag = pstr[tmp.number - 1].selected)){while (getchar() != '\n');if (flag){puts("此座位已被预定,请重新选择座位:");flag = 0 ;}elseputs("非法输入,请重新输入座位号:");}while (getchar() != '\n') ;tmp.selected = 1 ; //锁定此座位puts("请输入您的名:");while (!s_gets(tmp.name , NAME_LEN))puts("非法输入,请重新输入您的名:");puts("请输入您的姓:");while (!s_gets(tmp.s_name , NAME_LEN)) puts("非法输入,请重新输入您的姓:");puts("======================================");printf("座位号: %d\n名:%s\n姓:%s\n" , tmp.number , tmp.name , tmp.s_name);puts("确认预约此座吗?(y/n):");while (!scanf(" %c" , &ch) || !isalpha(ch = tolower(ch))) ;if (ch == 'y'){pstr[tmp.number - 1] = tmp ;return 1 ; }elsereturn 0 ;
}int delte_seat(seat * pstr , int n)
{int num ;int flag = 0;char ch ;puts("请输入您要删除的座位号:");while (!scanf(" %d" , &num) || num < 1 || num > n || (flag = !pstr[num - 1].selected)){while (getchar() != '\n');if (flag){puts("取消预约失败,此座位并未被预约");flag = 0 ;}elseputs("非法输入,请重新输入要取消预约的座位号:");}while (getchar() != '\n') ;puts("======================================");printf("座位号: %d\n名:%s\n姓:%s\n" , pstr[num - 1].number , pstr[num - 1].name , pstr[num - 1].s_name);puts("确认此座取消预约吗?(y/n):");while (!scanf(" %c" , &ch) || !isalpha(ch = tolower(ch))) ;if (ch == 'y'){pstr[num - 1].selected = 0 ;pstr[num - 1].name[0] = '\0' ;pstr[num - 1].s_name[0] = '\0' ;return 1 ; }elsereturn 0 ;
}char * s_gets(char * st , int n)
{char * ret_value = NULL ;char * find ;if (ret_value = fgets(st , n , stdin)){if (find = (strchr(st , '\n')))*find = '\0' ;else while (getchar() != '\n') ;}return ret_value ;
}
no9.c
//巨人航空公司(编程练习8)需要另一架飞机(容量相同),每天飞4班(航班102 , 311 ,444 , 519).把程序扩展为可以处理4个航班
//.用一个顶层菜单提供航班选择退出.选择一个特定航班,就会出现和编程练习8类似的菜单.但是该菜单需要添加一个新选项:确认
//座位分配.而且菜单中的退出是返回顶层菜单.每次显示都要指明当前正在处理的航班号.另外,座位分配显示要指明确认状态.
# include <stdio.h>
# include <ctype.h>
# include <windows.h># define FLIGHT_COUNT 4
# define SEAT_COUNT 12
# define NAME_LEN 50 typedef struct
{int number ;int selected ;char name[NAME_LEN] ;char s_name[NAME_LEN];
}seat;int initialize_airline(seat * pstr , int r , int c);
void print_menu(int n);
char choice_menu(int n);
int switch_menu(int choice , seat * pstr);
int empty_seat_count(const seat * pstr , int n);
int show_seat_list(const seat * pstr , int n);
int sort_seat_list(seat * pstr , int n);
int choice_seat(seat * pstr , int n);
int delte_seat(seat * pstr , int n);
char * s_gets(char * st , int n);
void print_flight(void);
char choice_flight(void);
int flight_switch(char ch);int main(void)
{seat airline[FLIGHT_COUNT][SEAT_COUNT] ;int num ;initialize_airline(*airline, FLIGHT_COUNT ,SEAT_COUNT); //初始化座位/*for (int i = 0 ; i < FLIGHT_COUNT ; i++){for (int j = 0 ; j < SEAT_COUNT ; j++)printf("%d %d %s %s\n" , airline[i][j].number , airline[i][j].selected ,airline[i][j].name , airline[i][j].s_name);if ((i + 1 % 2) == 0)putchar('\n');}*/while (num = flight_switch(choice_flight())){if (num > 0)while (switch_menu(choice_menu(num - 1) , airline[num - 1])) ;}puts("再见,欢迎下次乘坐.祝您生活愉快");return 0 ;
}int initialize_airline(seat * pstr , int r , int c)
{int i ;int j ;for (i = 0 ; i < r ; i++){for (j = 0 ; j < c ; j++){(pstr + (i * c + j))->number = j + 1 ;(pstr + (i * c + j))->selected = 0 ;(pstr + (i * c + j))->name[0] = '\0' ;(pstr + (i * c + j))->s_name[0] = '\0' ;}}return ((i * j) == (r * c) ? (i * j) : 0) ;
}int flight_switch(char ch)
{switch (ch){case 'a' ://厦航102return 1 ;break ;case 'b' ://国航311return 2 ;break ;case 'c' ://马航444return 3 ;break ;case 'd' ://南航519return 4 ;break ;case 'e' ://退出return 0 ;break ;default ://错误puts("无效选择,请重新选择");system("pause");return -1 ;break ;}
}char choice_menu(int n)
{char ch ;print_menu(n);while (!scanf(" %c" , &ch) || !isalpha(ch)){while (getchar() != '\n') ;puts("输入非法,请重新输入");}while (getchar() != '\n') ;return tolower(ch) ;
}void print_menu(int n)
{static const char * menu[] = {"请选择所要执行的操作:","a) 显示剩余未预定的座位数","b) 显示座位列表","c) 按首字母排序显示座位列表","d) 预定座位","e) 取消预定座位","f) 返回上一级菜单"};static const char * flight[] = {"厦航102" ,"国航311" ,"马航444" ,"南航519" ,};system("cls");printf("您选择的是[%s]航班\n", flight[n]);puts("-------------------------------------------------");for (int i = 0 ; i < sizeof(menu) / sizeof(menu[0]) ; i++)puts(menu[i]);
}int switch_menu(int choice , seat * pstr)
{switch (choice){case 'a' ://显示未预定的座位数量empty_seat_count(pstr , SEAT_COUNT);system("pause");return 1;case 'b' ://显示空的座位列表show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'c' ://按字母顺序显示座位列表sort_seat_list(pstr , SEAT_COUNT) ;system("pause");return 1 ;case 'd' ://为客户分配座位choice_seat(pstr , SEAT_COUNT);system("cls");show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'e' ://删除座位分配delte_seat(pstr , SEAT_COUNT);system("cls");show_seat_list(pstr , SEAT_COUNT);system("pause");return 1 ;case 'f' ://退出return 0 ;default ://错误选择puts("无效选择,请重新选择");system("pause");return 1 ;}
}int empty_seat_count(const seat * pstr , int n)
{int count = 0 ;for (int i = 0 ; i < n ; i++){if (pstr[i].selected == 0)count++ ;}printf("现在空座为还剩%d个\n" , count);return count ;
}int show_seat_list(const seat * pstr , int n)
{int i ;puts("当前座位信息:");/*for (i = 0 ; i < n ; i++){if (pstr[i].selected == 0)printf("座位号: %2d (空)\n" , pstr[i].number);}*/for (i = 0 ; i < n ; i++)printf("座位号: %-5d %-5s 名:%-20s 姓:%-20s\n" ,pstr[i].number ,pstr[i].selected ? "已预订" : "未预定" ,pstr[i].name ,pstr[i].s_name );return i ;
}int sort_seat_list(seat * pstr , int n)
{seat ** pstr_arr ;seat * tmp ;int min ;pstr_arr = (seat **)calloc( n , sizeof(seat *));for (int i = 0 ; i < n ; i++)pstr_arr[i] = &pstr[i] ;for (int i = 0 ; i < n - 1; i++){/*for (int j = 0 ; j < n - 1 - i ; j++){if (strcmp(pstr_arr[j]->name , pstr_arr[j + 1]->name) < 0){tmp = pstr_arr[j] ;pstr_arr[j] = pstr_arr[j + 1] ;pstr_arr[j + 1] = tmp ;}}*////*min = i ;for (int j = i + 1 ; j < n ; j++) if (strcmp(pstr_arr[min]->name , pstr_arr[j]->name) > 0)min = j ;if (min != i){tmp = pstr_arr[i] ;pstr_arr[i] = pstr_arr[min] ;pstr_arr[min] = tmp ;}//*/}for (int i = 0 ; i < n ; i++)printf("座位号: %-5d %-5s 名:%-20s 姓:%-20s\n" ,pstr_arr[i]->number ,pstr_arr[i]->selected ? "已预订" : "未预定" ,pstr_arr[i]->name ,pstr_arr[i]->s_name );free(pstr_arr);}int choice_seat(seat * pstr , int n)
{seat tmp ;char ch ;int flag = 0;puts("请输入您要挑选的座位号:");while (!scanf(" %d" , &tmp.number) || tmp.number < 1 || tmp.number > n || (flag = pstr[tmp.number - 1].selected)){while (getchar() != '\n');if (flag){puts("此座位已被预定,请重新选择座位:");flag = 0 ;}elseputs("非法输入,请重新输入座位号:");}while (getchar() != '\n') ;tmp.selected = 1 ; //锁定此座位puts("请输入您的名:");while (!s_gets(tmp.name , NAME_LEN))puts("非法输入,请重新输入您的名:");puts("请输入您的姓:");while (!s_gets(tmp.s_name , NAME_LEN)) puts("非法输入,请重新输入您的姓:");puts("======================================");printf("座位号: %d\n名:%s\n姓:%s\n" , tmp.number , tmp.name , tmp.s_name);puts("确认预约此座吗?(y/n):");while (!scanf(" %c" , &ch) || !isalpha(ch = tolower(ch))) ;if (ch == 'y'){pstr[tmp.number - 1] = tmp ;return 1 ; }elsereturn 0 ;
}int delte_seat(seat * pstr , int n)
{int num ;int flag = 0;char ch ;puts("请输入您要删除的座位号:(0 退出)");while (!scanf(" %d" , &num) || num < 1 || num > n || (flag = !pstr[num - 1].selected)){while (getchar() != '\n');if (flag){puts("取消预约失败,此座位并未被预约");flag = 0 ;}else if (num == 0) //终止取消预约操作return 0 ;elseputs("非法输入,请重新输入要取消预约的座位号:");}while (getchar() != '\n') ;puts("======================================");printf("座位号: %d\n名:%s\n姓:%s\n" , pstr[num - 1].number , pstr[num - 1].name , pstr[num - 1].s_name);puts("确认此座取消预约吗?(y/n):");while (!scanf(" %c" , &ch) || !isalpha(ch = tolower(ch))) ;if (ch == 'y'){pstr[num - 1].selected = 0 ;pstr[num - 1].name[0] = '\0' ;pstr[num - 1].s_name[0] = '\0' ;return 1 ; }elsereturn 0 ;
}char * s_gets(char * st , int n)
{char * ret_value = NULL ;char * find ;if (ret_value = fgets(st , n , stdin)){if (find = (strchr(st , '\n')))*find = '\0' ;else while (getchar() != '\n') ;}return ret_value ;
}void print_flight(void)
{static const char * flight[] = {"请选择一驾航班:" ,"a) 厦航102" ,"b) 国航311" ,"c) 马航444" ,"d) 南航519" ,"e) 退出"};system("cls");for (int i = 0 ; i < sizeof(flight) / sizeof(flight[0]) ; i++){puts(flight[i]);}
}char choice_flight(void)
{int ch ;print_flight() ;while (!scanf(" %c" , &ch) || !isalpha(ch)){while (getchar() != '\n') ;puts("非法输入,请重新选择");}return tolower(ch) ;
}no10.c
//编写一个程序,通过一个函数指针数组实现菜单.例如.选择菜单中的a,将激活由该数组第1个元素指向的函数# include <stdio.h>
# include <windows.h>
# include <math.h>void print_menu(void);
int choice_menu(void);
void calculation(int cmd);
double fun_add(double x , double y);
double fun_sub(double x , double y);
double fun_mul(double x , double y);
double fun_div (double x , double y);
double get_number(void);int main(void)
{int n ;while ((n = choice_menu())){calculation(n - 1);}return 0 ;
}int choice_menu(void)
{int num ;print_menu();for (int i = 0 ; !scanf(" %d", &num) || num < 1 || num > 5 ; i++){while (getchar() != '\n');if ((i + 1) % 10 == 0)print_menu();puts("无效输入,请输入整数");}while (getchar() != '\n') ;return (num == 5 ? 0 : num );
}
void print_menu(void)
{static const char * menu[] = {"======================================" ,"请选择您需要的功能:" ,"1 加 2 减" ,"3 乘 4 除" ,"5 退出" ,"======================================" };system("cls");for (int i = 0 ; i < sizeof(menu) / sizeof(menu[0]) ; i++)puts(menu[i]);
}void calculation(int cmd)
{double r , n1 , n2 ;double (*f[4])(double x ,double y) = {fun_add , fun_sub , fun_mul , fun_div} ;puts("请输入您要计算的第一个数:");n1 = get_number();puts("请输入您要计算的第二个数:");n2 = get_number();printf("计算结果为: %.2lf\n" , f[cmd](n1 , n2));system("pause");
}double fun_add(double x , double y)
{double sum = 0 ;sum = x + y ;return sum ;
}double fun_sub(double x , double y)
{double results = 0; results = x - y ;return results ;
}double fun_mul(double x , double y)
{double results = 0 ;results = x * y ;return results ;
}double fun_div (double x , double y)
{double results = 0 ;if (y == 0){fputs("参数错误:除数不能为0\n" , stderr);}elseresults = x / y ;return results ;
}double get_number(void)
{double x = 0;while (!scanf(" %lf" , &x)){while (getchar() != '\n') ;puts("无效输入,请输入正确的数字");}while (getchar() != '\n') ;return x ;
}
no11.c
// 编写一个名为transform()的函数,接受4个参数:内含double类型数据的源数组名,内含double类型数据的目标数组名,
// 一个表示数组元素个数的int类型参数,函数名(或等价的函数指针).transform()函数应把指针函数应用于源数组的每
// 个元素,并把返回值储存在目标数组中.例如:
// transform(source , target , 100 , sin) ;
// 该声明会把target[0]设置为sin(source[0]),等等,共有100个元素.在一个程序中调用transform()4次,以测试函数.分
// 别使用math.h函数库中的两个函数以及自定义的两个函数座位参数.# include <stdio.h>
# include <windows.h>
# include <math.h>int transform(double * source , double * traget , int n , double (*pfun)(double x));
void print_results(const double * source , int n);int main(void)
{double source[4] = {1 , 2 , 3 , 4};double traget[4] = {0};transform(source , traget , 4 , sin);puts("source :");print_results(source , 4);puts("traget :");print_results(traget , 4);return 0 ;
}int transform(double * source , double * traget , int n , double (*pfun)(double x))
{int i = 0 ;for (i = 0 ; i < n ; i++)traget[i] = pfun(source[i]);return i ;
}void print_results(const double * source , int n)
{for (int i = 0 ; i < n ; i++){printf("%lf " , source[i]);}putchar('\n');
}
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