C语言简单示例(宏定义一应用)

来源：互联网发布：c语言else if语句用法编辑：程序博客网时间：2024/06/07 03:10

以下代码来自播布客视频,亚嵌李明老师课程.

#include<stdio.h>#if 0void swap(int a, int b){        char tmp;        tmp = b;        b = a;        a = tmp;}#endif#define SWAP(a, b)   \do{                  \        char tmp;    \                     \        tmp = b;     \        b = a;       \        a = tmp;     \}while(0)       void reverse(char buf[], int i){        int j = 0;        /* string "321" to string "123" */        for(j = 0; j< i/2; j++)        {                if(j >= 0)                        SWAP(buf[j],buf[i-1-j]);                else                        printf("error\n");        }}void itoa(int num, char buf[]){        int i = 0;        /* num 123 to string "321" */        do        {                buf[i] = num % 10 + '0';                i++;                num /= 10;        }while(num != 0);        buf[i] = '\0';        reverse(buf, i);        return;}int main(void){        int num = 123;        char buf[10];        printf("input a number\n");        scanf("%d", &num);        printf("numm = %d\n", num);        itoa(num,buf);        printf("2. buf = %s\n", buf);        return 0;}