if conditional not executing c++

#include<iostream>
#include<string>
#include<cstdio>
#include<cstdlib>
#include<bits/stdc++.h>
#include<algorithm>

using namespace std;
int main(int argc, char const *argv[])
{
    int n,d;
    cin>>n>>d;
    string a1("1");
    int count = 0;
    int sum[1000];
    string a[1000];
    for(int i=0;i<d;i++){
        cin>>a[i];
        for(int j=0;j<n;j++){

            if(a[j].compare(a1) == 0){
                count++;
            }
        }
        sum[i] = count;
        cout<<sum[i]<<endl;

    }
    int kill = 0;



for(int i=0;i<d;i++){
    if(sum[i] == 0){
        kill++;
    }
    else if(sum[i] == sum[i+1]){
        kill++;
    }

}

//cout<<kill<<endl;


    return 0;
}

I have to a comparision between every bit of string and 1, if bit is 1 then increament counter by 1, I have written this logic, but the if conditional isn't working, as It should execute when a[j] == 1, but it's not. Can someone help me out with this ? thanks in advanced.