程序代码：

#include <iostream>
#include <string>
using namespace std;

char *reverse(char *str)
{
    if(!str)
        return "";

    int len = strlen(str);
    int i,j;
    for(i=0,j=len-1;i<j;i++,j--)
    {
        char tmp = str[i];
        str[i] = str[j];
        str[j] = tmp;
    }

    return str;
}

void main()
{
    char string[] = "abcde";

    cout << reverse(string) << endl;
}