c语言简单的字符串翻转

#include <stdio.h>#include <string.h>#include <stdlib.h>void backstring(char ss[]){int len;len = strlen(ss);char str[len];;int i;int j = 0;for(i=len-1;i>=0;i--){str[j]=ss[i];j++;}str[j]='\0';printf("%s\n",str);}int main(int argc,char**argv){char s[]="1234";backstring(s);return 0;}

程序输出：4321