strrev的函数~~

字符串的反转函数，比较适合在校的学生~~

char * mystrrev(char *a)
{
    char *right = a;   //定义正常的字符串
    char *left = a;    //定义反向的字符串
    char ch;           //定义交换变量

    while (*right)                 
    right++;           
    right--;
    while (left < right)
    {
         ch = *left;
         *left++ = *right;
         *right-- = ch;
    }