简单字符串替换

#include <stdio.h>#include <string.h>int main(void){    int i = 0;    char str[20] = {0};    fgets(str,20,stdin);    while(str[i] != 0)    {        if(str[i] == ' ')        {            str[i] = '%';            i++;        }        else        {            i++;        }    }    printf("str = %s\n",str);    return 0;}