C语言程序设计余贞侠（课后习题答案）

本文章为C语言程序设计课后习题和答案

-------------------如有错误，欢迎及时评论区指出，目前自主学习不定时更新-------------------------

欢迎大家一起讨论，也欢迎大家一起学习相关的知识，多多交流，一起提高

第一章程序设计基础

第二章数据类型、运算符和表达式

第三章顺序结构程序设计

第四章选择结构程序设计

第五章循环结构程序设计

第六章模块化程序设计

第七章数组

第八章指针

第九章自定义数据类型

第十章文件

第一章程序设计基础

因都为文字叙述题和简答题（后续章节一样），所以暂不更新第一章。

第二章数据类型、运算符和表达式

1.略, 2.C, 3.D, 4.C, 5.A, 6.A, 7.C, 8.A, 9.A, 10.B, 11.A, 12.D, 13.B, 14.C, 16.略。

15.代码如下：

#include<stdio.h>
int main(){float F;//定义一个华氏度温度scanf("%f",&F);printf("C=%f ",5*(F-32)/9);//也可以定义一个C表示出return 0;
}

第三章顺序结构程序设计

1.(1)C, (2)B。

2.scanf缺少取地址符号'&',printf应该为%d。

3.(1)BOY换行 (2)12%,15.500000%。

4.略。

5.代码如下

(1)

#include<stdio.h>
int main(){int l,w;//定义长度和宽度int s=0,c=0;//定义面积和周长printf("请输入长度和宽度并用空格隔开：\n");scanf("%d %d",&l,&w);s=l*w;c=2*(l+w);printf("周长为:%d\n面积为:%d\n",c,s);return 0;
}

(2)

#include<stdio.h>
int main(){char Letter,letter;//定义大写字母和小写字母printf("输入一个大写字母：\n");Letter=getchar();letter=Letter+32;//大写字母为小写字母ASCII码+32printf("转换前：%c\tASCII码为：%d\n转换后：%c\tASCII码为：%d\n",Letter,Letter,letter,letter);return 0;
}

(3)

#include<stdio.h>
int main(){int num1,num2,num3,num4,num5;printf("请输入5个数：\n");scanf("%d%d%d%d%d",&num1,&num2,&num3,&num4,&num5);printf("计算结果为：\n");printf("%015.8lf",(float)num1/num2*num3+num4-num5);/*因为整数是6位，小数是8位，加上一位小数点，总共为15位*/return 0;
}

(4)

#include<stdio.h>
int main(){int num1;char ch1,ch2;float num2;printf("请输入4个数据(依次为1个整数、2个字符、1个实数)\n");scanf("%d %c %c %f",&num1,&ch1,&ch2,&num2);printf("这4个数据倒序为：\n");printf("4-%.2f 3-%c 2-%c 1-%d",num2,ch2,ch1,num1);//参考书上输出所以保留两位return 0;
}

(5)

#include<stdio.h>
int main(){int y,m,d;printf("please input a date:\n");scanf("%d-%d-%d",&y,&m,&d);printf("the date is:\n");printf("%d/%d/%d",y,m,d);//若需要考虑月和日0开头则格式化输出即可return 0;
}

(6)

#include<stdio.h>
int main(){int num,sum;//sum用于统计;printf("请输入一位三位数整数\n");scanf("%d",&num);printf("百位为%d 十位为%d 个位为%d ",num/100,num/10%10,num%10);sum=num/100+num/10%10+num%10;printf("位数之和为%d \n",sum);//可以循环依次取余相加也可return 0;
}

(7)

#include<stdio.h>
#include<math.h>//方便使用根号公式
int main(){int a,b,c;a=4,b=4;//手动输入则修改为读入即可c=sqrt(a*a+b*b);//c等于根号下a方+b方printf("斜边为:%d\n",c);//会丢掉小数位return 0;
}

(8)略

(9)

#include<stdio.h>
#include<math.h>//方便使用根号公式
int main(){int r1,r2;//定义小圆半径和大圆半径printf("依次输入小圆半径和大圆半径：\n");scanf("%d %d",&r1,&r2);float PI=3.14,S;//圆周率和圆环面积S=PI*(r2*r2-r1*r1);printf("%.3f \n",S);return 0;
}

-----------------------------------------------------------------------------------------------------------------6.30日更新

第四章选择结构程序设计

(1)

#include<stdio.h>
int main(){int num1,num2,num3,num4;int max1,max2;printf("请输入4个数字：\n");scanf("%d %d %d %d",&num1,&num2,&num3,&num4);if(num1>=num2){max1=num1;max2=num2;}else{max1=num2;max2=num1;}if(max1<=num3){max2=max1;max1=num3;}else if(max2<=num3){max2=num3;}if(max1<=num4){max2=max1;max1=num4;}else if(max2<=num4){max2=num4;}printf("最大值是%d,次大值是%d\n",max1,max2);return 0;
}

(2)

#include<stdio.h>
int main(){int x;printf("请输入x的数值：\n");scanf("%d",&x);if(x<1){printf("y的值为%d \n",x);}else if(x>=30){printf("y的值为%d \n",7*x-3);}else{printf("y的值为%d\n",3*x+5);}return 0;
}

(3)

#include<stdio.h>
int main(){int x;printf("请输入x的数值：\n");scanf("%d",&x);if(x>=0){printf("x的值为%d \n",x);}else{printf("x的绝对值为%d\n",-x);}return 0;
}

(4)

 #include<stdio.h>#include<math.h>//方便使用abs函数判断两数之差
int main(){int a,b,c;int p,s;//辅助记录函数面积printf("请输入a b c的数值：\n");scanf("%d %d %d",&a,&b,&c);if(a+b>c && abs(a-b)<c){//可能为负数所以要加绝对值printf("可以构成三角形\n");}else if(a+c>b && abs(a-c)<b){printf("可以构成三角形\n");}else if(b+c>a && abs(b-c)<a){printf("可以构成三角形\n");}else {printf("不可以构成三角形\n");}p=(a+b+c)/2;s=sqrt(p*(p-a)*(p-b)*(p-c));printf("三角形的面积为%d",s);return 0;
}

(5)

#include<stdio.h>
int main(){char ch;printf("请输入一个字符：\n");ch=getchar();if(ch>='a' && ch<='z'){printf("大写为%c \n",ch-32);}else if(ch>='A' && ch<='Z'){printf("小写为%c \n",ch+32);}else if(ch>='0' && ch<='9'){printf("ASCII码为 %d \n",ch);}else{printf("@ \n");}return 0;
}

(6)

#include<stdio.h>int main(){double BMI,kg,m;printf("请输入身高(m)和体重(kg)：\n");scanf("%lf %lf",&m,&kg);BMI=kg/(m*m);if(BMI<18.5){printf("体重过低\n");}else if(BMI>=18.5 && BMI<24){printf("正常范围\n");}else if(BMI>=24 && BMI<28){printf("超重\n");}else{printf("肥胖\n");}return 0;
}

(7)

 #include<stdio.h>int main(){int num1,num2,num3,num4;int max1,max2,max3,max4;printf("请输入4个数字：\n");scanf("%d %d %d %d",&num1,&num2,&num3,&num4);max1=max2=max3=max4=0;if(num1>=num2){max1=num1;max2=num2;}else{max1=num2;max2=num1;}if(max1<=num3){max3=max2;max2=max1;max1=num3;}else if(max2<=num3){max3=max2;max2=num3;}else{max3=num3;}if(max1<=num4){max4=max2;max2=max1;max1=num4;}else if(max2<=num4){max4=max2;max2=num4;}else{max4=num4;}if(max3>=max4){printf("%d %d %d %d\n",max1,max2,max3,max4);//本章输出前两位大小也可以用此方法}else{printf("%d %d %d %d\n",max1,max2,max4,max3);}return 0;
}

第五章循环结构程序设计

(1)

#include <stdio.h>
int main(){int n,fac=1,sum=0;printf("请输入n的值：\n");scanf("%d",&n);for(int i=1;i<=n;i++){for(int k=i;k>0;k--){fac*=k;}sum+=fac;fac=1;}printf("%d的阶乘加和为%d ",n,sum);return 0;
}

(2)

#include <stdio.h>
int main(){int sum=0;printf("1000以内的完数有：");for(int i=1;i<1000;i++){for(int k=1;k<i;k++){if(!(i%k)){sum+=k;}}if(sum==i){printf("%d ",i);}sum=0;}return 0;
}

(3)

#include <stdio.h>
int main(){int m,n,min;printf("请输入m和n：\n");scanf("%d %d",&m,&n);if(n>m){min=m;m=n;n=min;}for(int i=n;i>0;i--){if(n%i==0&&m%i==0){min=i;break;}}printf("最大公约数为%d ",min);return 0;
}

(4)

#include <stdio.h>
int main(){double sum,h;//定义总米数和高度h=100;sum=100;//因为只有第一次是单独一次下落for(int i=1;i<10;i++){h/=2;sum+=h*2;}printf("总经过长度%lf,第8次反弹高度为%lf",sum,h);return 0;
}

(5)

#include <stdio.h>
int main(){printf("请输入一串字符:\n");int sum1,sum2,sum3;char ch;sum1=sum2=sum3=0;while((ch=getchar())!='\n'){if(ch>='a' && ch<='z'){sum1++;}else if(ch>='A' && ch<='Z'){sum1++;}else if(ch>='0' && ch<='9'){sum2++;}else{sum3++;}}printf("英文字母次数为%d 数字为次数为%d 其他字符次数为%d ",sum1,sum2,sum3);return 0;
}

(6)

#include <stdio.h>
int main(){printf("请输入任意个整数空格隔开，用-888表示结束:\n");int num1,max,min;num1=0;scanf("%d",&num1);if(num1==-888){return 0;}max=min=num1;while(num1 != -888){if(num1>max){max=num1;}else if(num1<min){min=num1;}scanf("%d",&num1);}printf("最大值为%d,最小值为%d",max,min);return 0;
}

(7)

#include <stdio.h>
int main(){int one,five,ten;for(ten=5;ten<=10;ten+=5){for(five=5;five<=20;five+=5){for(one=5;one<=100;one+=5){if(one+five*5+ten*10==100){printf("一元的要%d张，五元的要%d张，十元的要%d张\n",one,five,ten);}}}}
}

(8)

#include <stdio.h>
int main(){int g,m,x;//分别是公鸡 母鸡 小鸡for(g=1;g<=20;g++){for(m=1;m<=33;m++){for(x=1;x<=330;x++){if(x/3.0+m*3+g*5==100&&x+m+g==100){printf("小鸡%3d只，母鸡%3d只，公鸡%3d只\n",x,m,g);}}}}return 0;
}

--------------------------------------------------------------------------------------------------7.2更新

第六章模块化程序设计

(1)

#include<stdio.h>
#include<math.h>//方便使用根号公式
void S(int r1,int r2);
int main(){int r1,r2;//定义小圆半径和大圆半径printf("依次输入小圆半径和大圆半径：\n");scanf("%d %d",&r1,&r2);S(r1,r2);return 0;
}
void S(int r1,int r2){float PI=3.14,S;//圆周率和圆环面积S=PI*(r2*r2-r1*r1);printf("%.3f \n",S);
}

(2)

#include <stdio.h>
void M(int sum);
int main(){int sum=0;printf("1000以内的完数有：");M(sum);return 0;
}
void M(int sum){for(int i=1;i<1000;i++){for(int k=1;k<i;k++){if(!(i%k)){sum+=k;}}if(sum==i){printf("%d ",i);}sum=0;}
}

(3)

#include <stdio.h>
int Zd(int m,int n);//最大公约数
int Zx(int m,int n);//最小公倍数
int main(){int m,n,min,max;printf("请输入m和n：\n");scanf("%d %d",&m,&n);max=Zd(m,n);min=Zx(m,n);printf("最大公约数为%d 最小公倍数%d",max,min);return 0;
}
int Zd(int m,int n){int a=0;if(n>m){a=m;m=n;n=a;}for(int i=n;i>0;i--){if(n%i==0&&m%i==0){a=i;return a;}}return -1;
}
int Zx(int m,int n){int a=0;if(n>m){a=m;m=n;n=a;}for(int i=m;i>=0;i--){if(m%i==0&&n%i==0){a=m/i*n;return a;}}return -1;
}

(4)

#include <stdio.h>
int judge1(int m);
int judge2(int m);
int main(){int m;printf("请输入一位五位数m：\n");scanf("%d",&m);if(judge1(m)){if (judge2(m)){printf("%d是回文数字\n",m);}}else{printf("%d不是回文数字\n",m);}return 0;
}
int judge1(int m){int flag=0;if(m%10==m/10000){flag=1;}return flag;
}
int judge2(int m){int flag=0;if(m/1000%10 == m/10%10){flag=1;}return flag;
}

(5)

#include <stdio.h>
void Dput( int m);
int main(){int m;printf("请输入一位数m：\n");//超过十位建议用char读入scanf("%d",&m);printf("逆序数为:\n");Dput(m);return 0;
}
void Dput( int m){int x=0;for(;m>0;m/=10){x=m%10;printf("%d ",x);}
}

(6)1.输出如下

 :var equal 0:static var equal 0:var equal 0:static var equal 1:var equal 0:static var equal 2

2.输出如下

 :the num equal 2:the internal block num equal 1:the num equal 3:the internal block num equal 2:the num equal 4:the internal block num equal 3

第七章数组

(1)

#include<stdio.h>
void Sort(float a[],int n);
int main()
{float a[100];int i,c=0;char ch;for(i=0;ch!='\n';i++){scanf("%f",&a[i]);ch=getchar();c++;}Sort(a,c);for(int j=0;j<c;j++){printf("%f ",a[j]);}return 0;
}
void Sort(float a[],int n){int temp,i,k;float tmp;temp=a[0];for(i=0;i<n;i++){temp=i;for(k=i+1;k<n;k++){if(a[k]<a[temp]){temp=k;}}if(temp!=i){tmp=a[i];a[i]=a[temp];a[temp]=tmp;}}
}

(2)

#include<stdio.h>
#include<math.h>
#define N 10
float average(int a[]);
int cmp(int a[],float sum);
int main()
{printf("请输入十个数：\n");int a[N]={0};int b=0;float sum=0.0;for(int i=0;i<N;i++){scanf("%d",&a[i]);}sum=average(a);b=cmp(a,sum);printf("平均值是%.2f,最接平均值的是%d",sum,a[b]);return 0;
}
float average(int a[]){float sum=0.0;for(int i=0;i<N;){sum+=a[i++];}return sum/N;
}
int cmp(int a[],float sum){int temp=0,k;float b[N]={0};for(int i=0;i<N;i++){b[i]=fabs(a[i]-sum);}for(k=0;k<N;k++){if(b[temp]>b[k]){temp=k;}}return temp;
}

(3)

#include<stdio.h>
#define N 10
void minimum(int a[N][N],int min);
void maximum(int a[N][N],int max);
int main()
{int a[N][N];int max,min;max=min=a[0][0];minimum(a,min);maximum(a,max);return 0;
}
void minimum(int a[N][N],int min){int row,con;for(int i=0;i<=N;i++){for(int k=0;k<N;k++){if(a[i][k]<min){min=a[i][k];row=i;con=k;}}}printf("最小值是%d，第%d行和第%d列\n",min,row,con);
}
void maximum(int a[N][N],int max){int row,con;//定义行和列for(int i=0;i<=N;i++){for(int k=0;k<N;k++){if(a[i][k]>max){max=a[i][k];row=i;con=k;}}}printf("最大值是%d，第%d行和第%d列\n",max,row,con);
}

(4)

#include<stdio.h>
#define N 3
void row(int a[N][N]);
void con(int a[N][N]);
int main()
{int a[N][N]={};for(int i=0;i<N;i++){for(int k=0;k<N;k++){scanf("%d",&a[i][k]);}}row(a);printf("----------------\n");con(a);return 0;
}
void row(int a[N][N]){int sum=0,count=1;for(int i=0;i<N;i++){for(int k=0;k<N;k++){sum+=a[i][k];}printf("第%d行的值为%d\n",count,sum);count++;sum=0;}
}
void con(int a[N][N]){int sum=0,count=1;for(int i=0;i<N;i++){for(int k=0;k<N;k++){sum+=a[k][i];}printf("第%d列的值为%d\n",count,sum);count++;sum=0;}
}

(5)

#include<stdio.h>
#include<string.h>
int compare(char a[][100]);
int main()
{   printf("请输入三串字符:\n");char a[3][100]={};for(int i=0;i<3;i++){gets(a[i]);}printf("最大的字符串是%s",a[compare(a)]);return 0;
}
int compare(char a[][100]){int max=0;for(int i=0;i<3;i++){if(strcmp(a[i],a[i+1])>0){max=i;}else{max=i+1;}}return max;
}

(6)

#include<stdio.h>
#include<string.h>
#define N 40
int mystrcpy(char a[],char b[]);
int main()
{char s1[N]="I love you everday";char s2[]="I love English";if(mystrcpy(s1,s2)){printf("复制成功，内容为%s",s1);}else{printf("复制失败");}return 0;
}
int mystrcpy(char a[],char b[]){int i;if(strlen(b)>strlen(a)){return 0;}for(i=0;b[i]!='\0';i++){a[i]=b[i];}a[i]='\0';return 1;
}

(7)

#include<stdio.h>
#include<string.h>
void transform(long int sum,char a[100]);
int main()
{   printf("请输入一串数字:\n");char a[100];gets(a);long int sum=0;//-2^31~2^31-1transform(sum,a);return 0;
}
void transform(long int sum,char a[100]){int flag=0,i=0;if(a[0]=='-'){flag=1;i++;}for(i=i;a[i]!='\0';i++){sum=sum*10+(a[i]-'0');}if(flag){printf("%ld ",sum*-1);}else{printf("%ld ",sum);}
}

-----------------------------------------------------------7.5更新

第八章指针

(1)

#include<stdio.h>
void swap(int *x,int *y);
int main()
{int a,b;printf("请输入a和b的值:\n");scanf("%d %d",&a,&b);swap(&a,&b);printf("交换后:\na=%d b=%d",a,b);return 0;
}
void swap(int *x,int *y){int t;t=*x;*x=*y;*y=t;
}

(2)

#include<stdio.h>
void max(int *p,int n);
void min(int *p,int n);
int main()
{int a[10]={0};int *p=a;printf("请输入十个数字\n");for(int i=0;i<10;i++){scanf("%d",p++);}p=a;max(p,10);min(p,10);return 0;
}
void max(int *p,int n){int num=*p;for(int i=0;i<n;i++){if(num<*(p+i)){num=*(p+i);}}p=p-n;printf("%d ",num);
}
void min(int *p,int n){int num= *p;for(int i=0;i<n;i++){if(num>*(p+i)){num=*(p+i);}}p=p-n;printf("%d ",num);
}

(3)

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
void max(int a[5][5],int n);//每一行最大值
void Smax(int (*p)[5],int n);//整个数组最大值
int main()
{int a[5][5]={0,};int (*p)[5]=a;//int c=1;srand(time(0));for(int i=0;i<5;i++){for(int j=0;j<5;j++){*(*(p+i)+j)=rand()%100;//随机初始化数组}}printf("初始化矩阵为：\n");for(int i=0;i<5;i++){for(int k=0;k<5;k++){printf("%d\t",a[i][k]);}printf("\n");}max(a,5);printf("\n");Smax(p,5);return 0;
}
void max(int a[5][5],int n){int i,j;int maxnum;int count=1;for(i=0;i<n;i++){maxnum=a[i][0];for(j=0;j<n;j++){if(maxnum<a[i][j]){maxnum=a[i][j];}}printf("第%d行最大值是%d\n",count,maxnum);count++;}
}
void Smax(int (*p)[5],int n){int i,j,count;int  maxnum;maxnum=(*p)[0];for(i=0;i<n;i++){for(j=0;j<n;j++){if(maxnum<(*p)[j]){maxnum=(*p)[j];count=i+1;}}p++;}printf("最大值第%d行是%d\n",count,maxnum);
}

(4)

#include<stdio.h>
#include<stdlib.h>
void Dele(char *str1,char *str2);
int main()
{char a[100];gets(a);printf("输入的字符串为%s \n",a);char *str1,*str2;str1=str2=a;Dele(str1,str2);printf("删除后的字符串为%s \n",a);return 0;
}
void Dele(char *str1,char *str2){for(int i=0;*str1 !='\0';i++){if((*str1>='a'&&*str1<='z') ||( *str1>='A'&&*str1<='Z')){*str2=*str1;str2++;str1++;}else{str1++;}}*str2='\0';
}

(5)

#include<stdio.h>
#include<string.h>
char *strcopy(char *s1,char *s2);
int main()
{char a[100];char b[100];gets(a);printf("输入的字符串为%s \n",a);char *s1=a,*s2=b,*str;str=strcopy(s1,s2);printf("复制的的字符串为%s \n",str);return 0;
}
char *strcopy(char *s1,char *s2){char *s=s2;while(*s1!='\0'){*(s2++)=*(s1++);}*s2='\0';return s;
}

(6)

#include<stdio.h>
#include<string.h>
void Sort(char s[5][100]);
int main()
{char a[5][100];printf("输入五个字符串：\n");int i=0;while(i<5){gets(a[i]);i++;}Sort(a);i=0;printf("排序后字符串为:"\n");while(i<5){printf("%s\n",a[i]);i++;}return 0;
}
void Sort(char s[5][100]){char b[100];char *a=b;for(int i=1;i<5;i++){for(int j=0;j<5-i;j++){if(strcmp(s[j],s[j+1])>0){strcpy(a,s[j]);strcpy(s[j],s[j+1]);strcpy(s[j+1],a);}} }
}

------------------------------------------------------------------------7.7号更新

第九章自定义数据类型

结构体实在是太难了慢慢更新

(1)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
typedef struct{int year,month,day;
}date;
int count(int year,int month,int day);
int main(void)
{date a;int day=0;printf("请输入年月日如2022-02-22:\n");scanf("%d-%d-%d",&a.year,&a.month,&a.day);day=count(a.year,a.month,a.day);printf("是今年的第%d天",day);return 0;
}
int count(int year,int month,int day){int d[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};int flag=1;int sum=0;if((year%4==0&&year%100!=0)||year%400==0){flag=0;}for(int i=1;i<month;i++){sum+=d[i];}sum+=day;if(flag){return sum; }else if(flag==0&&month>2){return (sum+1);}else{return sum;   }}

(2)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
#define N 10
typedef struct{int fail;char num[11];char name[5];char age[2];float score[3];float avgscore;
}studen;
void Sort(studen s[]);
void Fail(studen s[]);
void Print(studen *s);
int main(void)
{studen s[N];printf("请输入10位学生的学号、姓名和年龄以及三门成绩(用空格隔开)：\n");for(int i=0;i<N;i++){s[i].avgscore=0.0;scanf("%s%s%s",s[i].num,s[i].name,s[i].age);for(int k=0;k<3;k++){scanf("%f",&s[i].score[k]);s[i].avgscore+=s[i].score[k];}s[i].avgscore/=3;}Sort(s);Fail(s);Print(s);return 0;
}
void Sort(studen s[]){studen a;for(int i=0;i<N;i++){for(int j=i+1;j<N;j++){if(s[i].avgscore < s[j].avgscore){a=s[i];s[i]=s[j];s[j]=a;}}}
}
void Fail(studen s[]){for(int i=0;i<N;i++){s[i].fail=0;for(int k=0;k<3;k++){if(s[i].score[k]<60.0){s[i].fail=1;break;}}}printf("不及格的学生信息如下:\n");printf("学号 姓名 年龄 三科成绩\n");for(int k=0;k<N;k++){if(s[k].fail){printf("%s %s %s ",s[k].num,s[k].name,s[k].age);for(int j=0;j<3;j++){printf("%.2f ",s[k].score[j]);}printf("\n");}}
}
void Print(studen *s){printf("排序学生信息如下:\n");printf("学号 姓名 年龄 三科成绩\n");for(int k=0;k<N;k++){printf("%s %s %s ",s[k].num,s[k].name,s[k].age);for(int j=0;j<3;j++){printf("%.2f ",s[k].score[j]);}printf("\n");}
}

(3)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
#define N 3
typedef struct a{char num[11];char name[5];char age[2];struct a *next;}studen;
void Scan(studen s[],int n);
int main(void)
{studen s[N];studen *head,*p;int i;Scan(s,N);head=&s[0];for( i=0;i<N;i++){s[i].next=&s[i+1];}s[i-1].next=NULL;//尾部标记一下为空p=head;while(p){printf("%s %s %s\n",p->num,p->name,p->age);p=p->next;}
}
void Scan(studen s[],int n){printf("请输入学号、姓名和年龄\n");for(int i=0;i<n;i++){scanf("%s%s%s",s[i].num,s[i].name,s[i].age);}
}

(4)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
typedef struct a{char num[11];float score;struct a *next;
}studen,*STU;
STU Create(int n);
int Find(studen *s);
void print(STU head);
int main(void)
{   STU head=NULL;int n;printf("请输入学生数目:\n");scanf("%d",&n);head=Create(n);print(head);Find(head);return 0;
}
STU Create(int n){int i=0;studen *head=NULL,*p1,*p2;while(i<n){p1=(studen *)malloc(sizeof(studen));p1->next=NULL;printf("请输入第%d个学生的信息:\n",i+1);scanf("%s %f",p1->num,&p1->score);if(head==NULL){head=p1;p2=p1;}else{p2->next=p1;p2=p1;}i++;}return head;
}
void print(STU head){studen *p=head;printf("录入学生信息如下:\n");printf("学号 成绩\n");while(p!=NULL){printf("%s %.2f\n",p->num,p->score);p=p->next;}
}
int Find(studen *s){char a[11];float b;printf("请输入要查找的学号和修改的信息:\n");scanf("%s %f",a,&b);for(;s!= NULL;s=s->next){if(strcmp(a,s->num)==0){printf("查找到学号为%s\n",s->num);printf("已修改%.2f为%.2f\n",s->score,b);s->score=b;return 1;}}printf("没有找到此学号\n");return 0;
}

(5)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
typedef struct a{char num[11];int date;struct a *next;}studen,*stu;
stu create(void);
stu Intersection(stu L1,stu L2);
void intput(studen *head);
int main(void)
{stu head=NULL,L1,L2;L1=create();L2=create();printf("第一个链表数据为:\n");intput(L1);printf("第二个链表数据为:\n");intput(L2);head=Intersection(L1,L2);printf("交集链表数据为:\n");intput(head);
}
stu create(void){int n;static int k=1;printf("请输入要建立的第%d个链表大小\n",k);k++;scanf("%d",&n);studen *head,*p,*q;int i=0;head=NULL;while(i<n){p=(stu)malloc(sizeof(studen));p->next=NULL;printf("请输入%d位的学号和成绩:",i+1);scanf("%s%d",p->num,&p->date);if(head==NULL){head=p;q=p;}else{q->next=p;q=p;}i++;}return head;
}
stu Intersection(stu L1,stu L2){studen *head,*p,*q,*s;p=L1;q=L2;if(p==NULL&&q==NULL){return 0;}while(p!=NULL){q=L2;while(q!=NULL){if(strcmp(p->num,q->num)==0){if(head==NULL){head=p;s=p;}else{s->next=q;s=q;}}q=q->next;//需要考虑空间回收问题}p=p->next;}s->next=NULL;return head;
}
void intput(studen *head){studen *p;p=head;while(p){printf("%s %d\n",p->num,p->date);p=p->next;}
}

(6)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
typedef struct a{char num[11];int date;struct a *next;}studen,*stu;
stu create(stu *L);//创建带头指针的链表
void DeleteNode(stu L1,stu L2);
void intput(studen *head);
int main(void)
{stu L1,L2;create(&L1);//链表1create(&L2);//链表2printf("第一个链表数据为:\n");intput(L1);printf("第二个链表数据为:\n");intput(L2);DeleteNode(L1,L2);//删除1中含有2的数据printf("删除后的第一个链表:\n");intput(L1);
}
stu create(stu *L){int n;static int k=1;printf("请输入要建立的第%d个链表大小\n",k);k++;scanf("%d",&n);studen *p;(*L)=(stu)malloc(sizeof(studen));//创建空间(*L)->next=NULL;int i=0;while(i<n){//循环读入数据p=(stu)malloc(sizeof(studen));printf("请输入%d位的学号和成绩:",i+1);scanf("%s%d",p->num,&p->date);p->next=(*L)->next;(*L)->next=p;i++;}return 0;
}
void DeleteNode(stu L1,stu L2){studen *temp,*p,*q,*s,*h,*p1;p=(L1)->next;q=(L2)->next;h=(L1);s=p;if(p==NULL&&q==NULL){exit(0);}while(q!=NULL){p=s;//回到起点迭代比较while(p!=NULL){if(strcmp(q->num,p->num)==0){if(h->next==p){//头结点需要单独换算h->next=p->next;temp=p;p=p->next;free(temp);}else{//释放掉找到节点p1->next=p->next;temp=p;p=p->next;free(temp);}}if(p!=NULL){//链表是否为空p1=p;p=p->next;}}q=q->next;}}
void intput(studen *head){//输出链表数据studen *p;p=head->next;while(p){printf("%s %d\n",p->num,p->date);p=p->next;}
}

----------------------------------------------------------------------------------------7.13就先到这里吧

(7)

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
typedef struct a{char num[11];int date;struct a *next;}studen,*stu;
stu create(void);
stu Union(stu L1,stu L2);
void intput(studen *head);
int main(void)
{stu head=NULL,L1,L2;L1=create();L2=create();printf("第一个链表数据为:\n");intput(L1);printf("第二个链表数据为:\n");intput(L2);head=Union(L1,L2);printf("并集链表数据为:\n");intput(head);
}
stu create(void){int n;static int k=1;printf("请输入要建立的第%d个链表大小\n",k);k++;scanf("%d",&n);studen *head,*p,*q;int i=0;head=NULL;while(i<n){p=(stu)malloc(sizeof(studen));p->next=NULL;printf("请输入%d位的学号和成绩:",i+1);scanf("%s%d",p->num,&p->date);if(head==NULL){head=p;q=p;}else{q->next=p;q=p;}i++;}return head;
}
stu Union(stu L1,stu L2){studen *head,*p,*q,*s;p=L1;q=L2;if(p==NULL&&q==NULL){return 0;}while(q!=NULL&&p!=NULL){if(strcmp(p->num,q->num)<0){if(head==NULL){head=p;s=p;}else{s->next=p;s=p;}p=p->next;}else if(strcmp(p->num,q->num)>0){if(head==NULL){head=q;s=q;}else{s->next=q;s=q;}q=q->next;}else{if(head==NULL){head=p;s=p;}else{s->next=p;s=p;}p=p->next;q=q->next;}}while(q){s->next=q;s=q;q=q->next;}while(p){s->next=p;s=q;p=p->next;}s->next=NULL;return head;
}
void intput(studen *head){studen *p;p=head;while(p){printf("%s %d\n",p->num,p->date);p=p->next;}
}

(8)

#include <stdio.h>
#include <stdlib.h>
typedef struct StuInfo{int date;struct StuInfo *next;
}student,*stu;
stu create();
stu Numberoff(stu h);
int main(){stu head;head=create();Numberoff(head);return 0;
}
stu create(){int n=1;student *head,*p,*s;head=NULL;while(n<11){p=(stu)malloc(sizeof(student));p->next=NULL;p->date=n;if(head==NULL){head=p;s=p;}else{s->next=p;s=p;}++n;}s->next=head;return head;
}
stu Numberoff(stu h){student *head,*p,*q;head=h;q=head;//记录头结点和当前位置节点qp=head;//让p等于头结点后面int n=9,count=1;while(n>0){if(count%3!=0){++count;q=p;p=p->next;}else{q->next=p->next;printf("淘汰编号%d\n",p->date);free(p);p=q->next;--n;count=1;}}head=p;printf("剩余节点%d\n",head->date);
}

-----------------------------------------------------------------7.14更新

第十章文件

(1)略

(2)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){char *p;char a[20];FILE *fp;fp=fopen("2.1.txt","r");if(fp==NULL){printf("File can not be opened\n");exit(0);}p=fgets(a,40,fp);while(p != NULL){printf("%s",p);;p=fgets(a,40,fp);}fclose(fp);return 0;
}

(3)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(){char p;char b[20];printf("请输入要创建的文件名\n");scanf("%s",b);strcat(b,".txt");FILE *fp,*fq;fp=fopen("3.1.txt","r");fq=fopen(b,"w+");if(fp==NULL||fq==NULL){printf("File can not be opened\n");exit(0);}else{printf("File created\n");}p=fgetc(fp);while(p != EOF){if(fputc(p,fq)==EOF){printf("fail");exit(0);}p=fgetc(fp);}printf("copy ok!");fclose(fp);fclose(fq);return 0;
}

(4)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct a{char name[10];int age;float Mscore;float Escore;float Yscore;
}stu;
int main(){stu b;//char *p;FILE *fp;fp=fopen("student.txt","w+");if(fp==NULL){printf("File can not be opened\n");exit(0);}for(int i=1;i<=5;i++){printf("请输入第%d个学生的信息(姓名 年龄 数学 英语 语文)\n",i);scanf("%s %d %f %f %f",b.name,&b.age,&b.Mscore,&b.Escore,&b.Yscore);fprintf(fp,"%s %d %.2f %.2f %.2f",b.name,b.age,b.Mscore,b.Escore,b.Yscore);fprintf(fp,"\n");}fclose(fp);return 0;
}

(5)

#include<stdio.h>
#include<stdlib.h>
#include<string.h>struct a{float average;//平均值char name[10];int age;float Mscore;//数学成绩float Escore;//英语float Yscore;//语文
}stu[5];
void Sort();
int main(){FILE *fp=fopen("student.txt","r");int i=0,j=0;do{j=fscanf(fp,"%s %d %f %f %f",stu[i].name,&stu[i].age,&stu[i].Mscore,&stu[i].Escore,&stu[i].Yscore);stu[i].average=(stu[i].Mscore+stu[i].Escore+stu[i].Yscore)/3;i++;}while(j==5);Sort();for(int i=0;i<5;i++){printf("%s %f\n",stu[i].name,stu[i].average);}fclose(fp);return 0;
}
void Sort(){struct a temp;//快速排序int k;for(int i=0;i<4;i++){k=i;for(int j=i+1;j<5;j++){if(stu[j].average>stu[k].average){k=j;}}if(i!=k){temp=stu[i];stu[i]=stu[k];stu[k]=temp;}}
}

(6)

#include <stdio.h>
#include <stdlib.h>
typedef  struct a{char name[10];int pirce;//单价int num;float money;//金额
}goods;int main(){FILE *fp = fopen("goods.txt", "wb");int n;goods a;printf("请输入要读入的商品个数\n");scanf("%d",&n);if(fp==NULL){printf("File can not be opened\n");exit(0);}for(int i=0;i<n;i++){printf("按顺序输入 名字 单价 数量 金额\n");scanf("%s %d %d %f",a.name,&a.pirce,&a.num,&a.money);fwrite(&a,sizeof(goods),1,fp);}
//  fclose(fp);/*测试输出代码*/
//      fp=fopen("goods.txt","rb");
//      printf("商品信息\n");
//      while(fread(&a,sizeof(goods),1,fp)==1){
//          printf("%s %d %d %.2f\n",a.name,a.pirce,a.num,a.money);
//      }fclose(fp);return 0;
}

(7)

#include<stdio.h>
#include<stdlib.h>
#define N 30
typedef  struct a{char name[10];int pirce;//单价int num;float money;//金额
}goods;
void Sort(goods a[],int n);
int main(){int i;FILE *fp=fopen("goods.txt","rb");goods a[N];for( i=0;i<N;i++){if(feof(fp)){break;}fread(&a[i],sizeof(goods),1,fp);}Sort(a,i-1);printf("产品排序如下:\n");for(int j=0;j<i-1;j++){printf("%s %d %d %.2f\n",a[j].name,a[j].pirce,a[j].num,a[j].money);}
}
void Sort(goods a[],int n){goods temp;int flag=0;//判断两个金额是否相同for(int i=0;i<n;i++){flag=1;for(int j=i+1;j<n;j++){if(a[i].money<a[j].money){temp=a[i];a[i]=a[j];a[j]=temp;}else if(flag&&a[i].pirce<a[j].pirce){temp=a[i];a[i]=a[j];a[j]=temp;}}}
}

----------------第一次尝试更新这种，还请大家看到错误多多包涵，谢谢大家，更新完毕！7.17