本部分包含常用关键字，define定义常量和宏，指针，结构体。
笔记：
?代码：
#define _CRT_SECURE_NO_WARNINGS 1
//1.2.2static修饰全局变量
static int a4 = 0;
int a5 = 100;
static int staticAdd(int x, int y)
{
?? ?int sum = x + y;
?? ?return sum;
}
int Add(int x, int y)
{
?? ?int sum = x + y;
?? ?return sum;
}
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
//1.1tydefe类型重新定义
typedef unsigned int u_int;
//1.2.1static修饰局部变量
void test01()
{
?? ?static int a3 = 0;
?? ?a3++;
?? ?printf("%d",a3);
}
//1.2.2static修饰全局变量
extern int a4;
extern int a5;
//1.2.3static修饰函数
extern int staticAdd(int x, int y);
extern int Add(int x, int y);
//2.1#define 定义常量
#define MAX 5
//2.2#define 定义宏
#define ADD(X,Y) ((X)+(Y))?
//4.结构体
struct Stu
{
?? ?char name[10];
?? ?int age;
?? ?float score;
};
int main()
{
?? ?//1.常见关键字
?? ?//auto int a1=0;
?? ?
?? ?//1.1tydefe类型重新定义
?? ?u_int a2 = 0;
?? ?
?? ?//1.2static
?? ?//1.2.1static修饰局部变量
?? ?printf("static静态变量：");
?? ?int i = 0;
?? ?while (i < 10)
?? ?{
?? ??? ?test01();
?? ??? ?i++;
?? ?}
?? ?//1.2.2static修饰全局变量
?? ?printf("\nstatic全局变量：a5:%d",a5);
?? ?//printf("static全局变量：a4:%d", a4);
?? ?
?? ?//1.2.3static修饰函数
?? ?int x = 10;
?? ?int y = 20;
?? ?int sum = Add(x, y);
?? ?//int sum = staticAdd(x, y);
?? ?printf("\nsum的值为%d",sum);
?? ?//2.#define 定义常量和宏
?? ?//2.1#define 定义常量
?? ?//2.2#define 定义宏
?? ?printf("\n常量和宏:%d",2*ADD(MAX,MAX));
?? ?//3.指针
?? ?char c1 = 'a';
?? ?char* c2 = &c1;
?? ?*c2 = 'b';
?? ?printf("\n指针:%c", *c2);
?? ?printf(" ?指针所占空间：%d", sizeof(int*));
?? ?//4.结构体
?? ?struct Stu one = { "mumu",10,100 };
?? ?printf("\n1.结构体的值为：名字%s年龄%d分数%f",one.name,one.age,one.score );
?? ?struct Stu* oneAdress = &one;
?? ?printf("\n2.结构体的值为：名字%s年龄%d分数%f", oneAdress->name, oneAdress->age, oneAdress->score);
}