不使用内建函数实现字符串逆序

void reverse(char* s)
{
    int i, slen, t;

    for (slen = 0; s[slen+1] != '\0'; slen++); 

    for (i = 0; i <= slen/2; i++) {
        t = s[i];         
        s[i] = s[slen-i]; 
        s[slen-i] = t;    
    }
}