count num of a string within another string

/*count string within another string*/
#include<stdio.h>
#include<string.h>
#include<stdlib.h>

void remLin(char *);

int main(){

    int index,checker,count=0,ls1,ls2;
    char *s1,*s2;

    printf("enter max length of s1:");
    scanf("%d",&ls1);
    printf("enter max length of s2:");
    scanf("%d",&ls2);

    while((getchar())!='\n'){}

    printf("\nenter s1: ");
    fgets( (s1=(char*)malloc(sizeof(char)*ls1)) , ls1 , stdin);
    remLin(s1);

    printf("\nenter s2: ");
    fgets( (s2=(char*)malloc(sizeof(char)*ls2)) , ls2 , stdin);
    remLin(s2);

    for(index=0,checker=0;s1[index]!='\0';index++){

        printf("\n\n at for() start>> location: %3d  s1 contains: %3c  count value: %3d",index,s1[index],count);

        while((s1[index]==s2[checker]) && ((s1[index])!='\0') && ((s2[checker])!='\0')){
            checker++;
            index++;
        }

        if(checker>0)
            index=index-1; // this compensates for one extra index increment at the end of while()

        if(checker==(strlen(s2))){
            count++;

        }
        checker=0;

        printf("\n at for()   end>> location: %3d  s1 contains: %3c  count value: %3d",index,s1[index],count);
    }

    printf("\n\ncount of %s in %s is: %d\n\n",s2,s1,count);


    return 0;
}

void remLin(char *str){
    int len=strlen(str);
    if(str[len-1]=='\n')
        str[len-1]='\0';
    realloc(str,len); // trims up the string
    printf("\nentered string: %s and its length: %d\n\n",str,strlen(str)); // strlen will not count the null terminator
}