Strcmp manually

#include <stdio.h>
#include <string.h>
int stringcmp();
int main()
{
    char s1[100],s2[100];
    gets(s1);
    gets(s2);
    int i=stringcmp(s1,s2);
    if(i==1)
        printf("1\n");
    if(i==-1)
        printf("-1\n");
    if(i==0)
        printf("0\n");

    return 0;
}
int stringcmp(char s1[100],char s2[100])
{
    int i;

    for(i=0;s1[i] != '\0' && s2[i] != '\0';i++){
        if(s1[i]>s2[i])
            return 1;
        if(s1[i]<s2[i])
            return -1;
    }
    if(strlen(s1[i])==strlen(s2[i]))
        return 0;
    if(strlen(s1[i])<strlen(s2[i]))
        return -1;
    if(strlen(s1[i])>strlen(s2[i]))
        return 1;
}