编辑代码

#include <stdio.h>
int main () 
{
    int i, resu;
    char s1[100],s2[100];
    printf("input string1:");
    gets(s1);
    printf("\ninput 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("\nresult:%d.\n",resu);
	return 0;
}