比较字符串s1和s2,若s1>s2，输出一个正数，若s1=s2,输出0,若s1<s2,输出一个负数。不用strcpy函数

#include<stdio.h>

int main ()
{
	int i;
	int resu;
	char s1[100];
	char s2[100];
	printf("input string1:");
	gets(s1);
	printf("\n");
	printf("input string2:");
	gets(s2);
	i = 0;
	while((s1[i] == s2[i]) && (s1[i] != '\0'))
	{
		i++;
	}
	if((s1[i] == '\0') && (s2[i]== '\0'))
	{
		resu = 0;
	}
	else
	{
		resu = s1[i]-s2[i];
	}
	printf("\n");
	printf("result:%d\n",resu);
	return 0;
}