#include<stdio.h>
#define LEN5
struct person {char name[8] ;char telNum[12];};
int main(intargc,const char* argv[]) {struct personcontacts[LEN];for (int i = 0; i < LEN ; i++) {scanf("%s%s",contacts[i].name,contacts[i].telNum);}for (int i = 0; i < LEN ; i++) {printf("姓名:%s,电话:%s\n",contacts[i].name,contacts[i].telNum);}return 0;
}

7).指向结构体变量的指针

8）.指针访问结构变量属于间接访问

#include<stdio.h>
#include<string.h>
struct person// struct是关键字  person是结构体名
{char name[8] ;char telNum[12];char *id;int age ;}per1; //结构体变量名int main(intargc,const char* argv[]) {structperson *p = &per1;//p是结构体指针//结构体指针间接访问成员值的方法//1).(*p).age; (*p)相当于per1//2).p->agep是结构体指针的时候写法(*p).age =10;(*p).id="2332";strcpy(p->name,"sdsd");// strcpy((*p).name,"sdsd");printf("%s\n",(*p).name);//incompatiblepointer to integer conversion to 'char' from char[5]//(*p)->age =100;//memberreference type 'struct person' is not a pointer ,maybe you//meant touse '.' to fix itreturn 0;
}

// main.c
// 结构体嵌套
//
// Created by CHINGWEI_MACPC on 15/11/6.
//  Copyright © 2015年 itcast. All rights reserved.
//#include<stdio.h>
struct Time {int hour ;int second ;int minite ;
};
struct Date
{int month;int day ;int year ;struct Timetime ;};
struct Student
{char name[8] ;int age ;float score ;struct Datebirthday;//可以嵌套自己类型的结构体指针//struct Student stu; //错误书写//structStudent *stu;};int main(intargc,const char* argv[]) {struct Studentstu1={"mike",18,89.5f,{2,12,2006,{10,23,13}}};printf("姓名:%s,年龄:%d,成绩:%f,生日:%02d/%02d/%d,时间:%02dh:%02dm:%ds\n",stu1.name,stu1.age,stu1.score,stu1.birthday.day,stu1.birthday.month,stu1.birthday.year,stu1.birthday.time.hour,stu1.birthday.time.minite,stu1.birthday.time.second);struct Person// struct 是关键字 person是结构体名{char name[8] ;int age ;struct Person*children;};//结构体嵌套指针的使用struct Personkim={"kim",20,NULL};structPerson p1 ={"小白",38,&kim};structPerson p2 ={"小白",38,&kim};printf("名字:%s，年纪:%d,儿子:%s\n",p1.name,p1.age,(*p1.children).name);//便于理解方法2 p2.children->nameprintf("名字:%s，年纪:%d,儿子:%s\n",p2.name,p2.age,p2.children->name);return 0;
}

结构体成员值作为函数参数

#include<stdio.h>
struct Student
{char name[8] ;float score ;};
void xiugai(floatscore )
{score=2.2f;
}
void printScore(structStudent stu)
{stu.score=2.2f;}
int main(intargc,const char* argv[]) {struct Studentstu1={"liu",12.3f};//1.结构体成员变量的成员值作为函数参数是值传递xiugai(stu1.score);printf("%s,%f\n",stu1.name,stu1.score);//2.用结构体变量作为函数的参数也是值传递printScore(stu1);printf("%s,%f\n",stu1.name,stu1.score);return 0;
}

结构体指针作为函数参数

将地址传递给函数

#include<stdio.h>
struct Student
{char name[8] ;float score ;};
void printScore(structStudent *stu)
{(*stu).score=2.2f;}
int main(intargc,const char* argv[]) {struct Studentstu1={"liu",12.3f};//liu,2.200000printScore(&stu1);printf("%s,%f\n",stu1.name,stu1.score);return 0;
}

枚举类型，基本数据类型，不是构造类型，因为不能再分解为任何基本类型

#include<stdio.h>
enumweek2{KMon1,KTue1,KWed1=5,KThur1,KFri1,KSta1,KSun1};
int main(intargc,const char* argv[]) {//定义变量 1.enum week1{KMon,KTue,KWed,KThur,KFri,KSta,KSun}iWeek1;//纠正型变量//2.enum week2iWeek2;//赋值iWeek1=KMon;//0iWeek2=KFri1;//7printf("%d\n",iWeek1);printf("%d\n",iWeek2);return 0;
}#include<stdio.h>
int sum(int a ,int b ){return a+b;
}
int main(intargc,const char* argv[]) {//1.基本数据类型typedef intINTERGER;//2.用在数组，给数组起别名typedefint ARRAY[5];//相当于ARRAY arr1 ={5,4,5,6,7};for (int i = 0; i < 5 ; i++) {printf("%d\n",arr1[i]);}//3.给结构体起别名 1)struct Person {int age ;char *name;};typedef struct Person P;P person2={22,"nmle"};printf("%d,%s\n",person2.age,person2.name);//3.给结构体起别名 2)typedef struct Car {int age ;char *name;}MYCAR;MYCAR car1 = {22,"sdsd"};printf("%d,%s\n",car1.age,car1.name);//3.给结构体起别名 3)typedef struct  {int age ;char *name;}IPHONE;IPHONE iP = {22,"sdsd"};printf("%d,%s\n",iP.age,iP.name);//4.给枚举起别名//typedef enumSex{Kse1,Kse2,Kse3}Isex;typedef enum  {Kw3,Kw2,Kw1}weekday;typedef enum Sex S ;S s1 ,s2;s1=Kse2;s2=Kse3;//5.给函数指针typedef int(*FUN)(int,int);FUN f1,f2;f1=sum;f2=sum;printf("%d\n",f1(2,3));printf("%d\n",f2(4,3));return 0;
}

预处理命令编译之前的工作

#开头的预处理命令

无参宏定义方法

#include<stdio.h>
#define LEN5
#define X (x*y+2*3)//最好加一个括号
#define Y  x*y+2*3#define PI3.14
#define R4
#define AREA PI*R*R//宏的嵌套
#define INT1 int//起别名int main(intargc,const char* argv[]) {#undef LENint a[R+4];//int a[6]int x=1 ,y=1;//1.宏的作用域 #undef宏名取消宏定义printf("X*X = %d\n",X*X);//49printf("Y*Y = %d\n",Y*Y);//13//2.宏的嵌套printf("%.f\n",AREA);//3.起别名INT1 a1 = 12;printf("a1 = %d\n",a1);return 0;
}无参数宏
#include<stdio.h>
#defineMAX(x,y) x+y
#defineequaL(m,n) m=x+y;n=x*y;
//1.宏名和形参之间不能有空格
int main(intargc,const char* argv[]) {// insertcode here...int r = 1 ;printf("%d\n",MAX(r, r));//2int x = 2 , y =3;int i ,j ;equaL(i, j);//4//         a+3+y,a-1+yprintf("%d,%d\n",i,j);return 0;
}// 有参宏应用#include<stdio.h>
#defineMAX(a,b) a>b?a:b
int main(intargc,const char* argv[]) {printf("Max(32,444)=%d\n",MAX(32, 444));return 0;
}//  typedef和define的区别
//
// Created by CHINGWEI_MACPC on 15/11/9.
//  Copyright © 2015年 itcast. All rights reserved.
//#include<stdio.h>
#defineINT1 int
typedefint INT2;
#defineINT3 int*
typedefint* INT4;
int main(intargc,const char* argv[]) {//宏定义变量int num = 10;INT1 a ,b ;a=10;b=10;printf("a = %d\n",a);//别名定义变量INT2 a1,b1;a1=100;b1=100;printf("a1 = %d\n",a1);//宏定义变量INT3 a3 ,b3 ;//只有 int *a3, 只有a3是指针变量a3=#b3=num;printf("a3 = %d,b3=%d\n",*a3,b3);//别名定义变量INT4 a4,b4;//a4,b4都是指针变量a4=#b4=#printf("a4 = %d,b4=%d\n",*a4,*b4);return 0;
}

条件编译：

发生在预处理阶段，在编译之前做的事情

核心:根据条件编译指定的代码

条件不同：编译的部分也不同，生成的目标文件也不同 .o大小不同

*/

#include<stdio.h>
#define  score100
int main(intargc,const char* argv[]) {
#if  score <60printf("Grade :F");
#elif score <=69printf("Grade : D");
#elif score <=79printf("Grade : C");
#elif score <=89printf("Grade : B");
#elseprintf("Grade : A");
#endifprintf("\n");return 0;
}

只编译一部分，

// 条件编译指令
//
// Created by CHINGWEI_MACPC on 15/11/9.
//  Copyright © 2015年 itcast. All rights reserved.
//#include<stdio.h>
#define DEBUG11
int main(intargc,const char* argv[]) {int a =0 ;
#ifdefDEBUG1a = 10 ;
#elsea=10000;
#endifprintf("%d\n",a);printf("%d\n",DEBUG);
#ifndef DEBUG2//如果没有定义宏a= 100 ;
#elsea=-1;
#endifprintf("%d\n",a);return 0;
}#include<stdio.h>
#define DEBUG11
#if DEBUG1 ==1
//显示调试信息
#defineLog(format,...) printf(format,## __VA_ARGS__);
//...表示可变参数          //##可以有一个或者多个
#else
//不显示调试信息
#defineLog(format,...);
#endifvoid test2(){Log("test------->%-5.2f ,%d,%d\n",10.3f,3,30);
}
void test(){Log("test ----- >%d\n",10);
}
int main(intargc,const char* argv[]) {Log("xxxxxxx----->%d\n",10);test();test2();return 0;
}