conver-a-non-negative-number-into-english-word

#include<iostream>
useing namespace std;

int main()
{
    
    return 0;
}





#include<bits/stdc++.h>
using namespace std;

vector<pair<int,string>>arr = {{1000000000,"Billion "}, {1000000,"Million "}, {1000,"Thousand "}, {100,"Hunded "},
 {90,"Ninety "}, {80,"Eighty "}, {70,"Seventy "}, {60,"Sixty "}, {50,"Fifty "}, {40,"Forty "}, {30,"Thirty "}, {20,"Twenty "},
 {19,"Nineteen "}, {18,"Eighteen "}, {17,"Seventeen "}, {16,"Sixteen "}, {15,"Fifteen "}, {14,"Fourteen "}, {13,"Thirteen "},
 {12,"Twelve "}, {11,"Eleven "}, {10,"Ten "}, {9,"Nine "}, {8,"Eight "}, {7,"Seven "}, {6,"Six "}, {5,"Five "}, {4,"Four "},
 {3,"Three "}, {2,"Two "}, {1,"One "}};

  string solve(int n){
    if(n==0){
        return "Zero ";
    }
    if(n>=10000000000){
        return "Invalid input please enter less than Billion";
    }
    for(auto i: arr){
        if(n >= i.first){
            string first = (n>=100 ? solve(n/i.first) : "");
            string second = i.second;
            string remAns = (n%i.first == 0 ? "" : solve(n % i.first));

            return first + second + remAns;
        }
    }
    return "";
}
int main()
{
    int n;
    cout<<"enter number"<<endl;
    cin>>n;
    string ans = solve(n);
    ans.pop_back();
    cout<<endl<<ans<<endl;
    return 0;
}