C语言笔试题（1）——将字符串对调显示

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

void reverse(char *str)
{
     char len = 0;
     char *p_top, *p_end;
     char temp;

     assert(str != NULL);
     len = strlen(str);           
     p_top = str;
     p_end = str + len - 1;

     while(p_top < p_end)
     {
           temp = *p_top;
           *p_top = *p_end;
           *p_end = temp;

           p_top++;
           p_end--;
     }
}

int main(void)
{
     char str[] = "ABCD1234efgh";

     reverse(str);

     printf("%s\n",str);
}