怎么编写：输入一个字符串，并将字符串反转，如“abcd”反转成“dcba”

char * mystrrev ( char * string ) {     char *start = string;     char *left = string;     char ch;     while (*string++)         ;     string -= 2;     while (left < string)     {     ch = *left;     *left++ = *string;     *string-- = ch;     }     return(start); } /////////////////cabs. vc字符串逆转 #include <stdio.h> char* rstr(char* a) {     char* p1, *p2, t;     p1 = p2 = a;     while(*p2) ++p2;     while(p1 < p2) {     t = *p1;     *p1++ = *--p2;     *p2 = t;     }     return a; } int main() {     char a[] = "abcd";     puts(rstr(a)); }