字符串判等 + double

#include<bits/stdc++.h>
using namespace std;
int main(){
    double n;
    cin>>n;
    string Da,Db;
    cin>>Da>>Db;
    int len=Da.size();
    double sum=0;
    for(int i=0;i<len;i++){
        if(Da[i]==Db[i]){
            sum++;
        }
    }
    double ggbond=sum/len;
    if(ggbond>=n) cout<<"yes";
    else cout<<"no";
    return 0;
}