C语言 带参数宏的原则

C语言 带参数的宏的原则
①整个值要括号
②参数出现的每个地方都要括号

示范:
错误例子:
①#define a1(x) (x*20)
②#define b1(x) (x)20
③#define a2(x) ((x20))
正确例子:
#define c(x) ((x)*20)

代码:
#include <stdio.h>
#define a1(x) (x*20)
#define b1(x) (x)*20
#define a2(x) ((x *20))
#define c(x) ((x)*20)
int main(){
printf(“a1(3+2) = %d\n”,a1(3+2));
printf(“a2(3+2) = %d\n”,a2(3+2));
printf(“180/b1(1) = %d\n”,180/b1(1));
printf(“180/c(1) = %d\n”,180/c(1));
printf(“c(3+2) = %d\n”,c(3+2));
return 0;
}

输出: