程序代码：

#include<stdio.h>
#include<string.h>
fun(char*w,int n)
{
    char t,*s1,*s2;
    s1=w;s2=w+n-1;
    while(s1<s2) {t=*s1++;*s1=*s2--;*s2=t;}
}
main()
{
    char*p;
    p="1234567";
    fun(p,strlen(p));
    puts(p);
}