please tell me the mistakes in this program(find no of sub string)

Question

#include <bits/stdc++.h>

using namespace std;
int FindSubString(char *a,char *b,int i);
int main()
{
    char a[100],b[100];
    fgets(a,100,stdin);
    cin>>b;
    int count=0,subcount;
    for(int i=0;i<sizeof(a);i++){
        subcount=FindSubString(a,b,i);
        if(subcount==sizeof(b))count++;
    }
    cout<<"total no of sub string : "<<count<<endl;
    return 0;
}
int FindSubString(char *a,char *b,int i){
    int k=0,count=0;
    for(int j=i;a[j]!='\0';j++){
        if(b[k]==a[i]){
            count++;
            k++;
        }
        else break;
    }
    return count;
}

Answer 1

The problem is likely in the line:

if(subcount==sizeof(b))count++;

This line assume the lenght of b is 100.  You can use strlen instead