Hamming Distance

#include <iostream>
#include <string>

using namespace std;

int hammingDistance(string s1,string s2)
{
    if( s1.size()!=s2.size() )
        return -1;
    int i,j,c=0;
    for(i=0;i<s1.size();i++)
        if( s1[i]!=s2[i] )
            c++;
    return c;
}
int main()
{
   cout << hammingDistance("1011100", "1001101") << endl;

   return 0;
}