17/18 Q2: Conversion from binary number to octal; X72799

#include <iostream>
using namespace std;

int binary2octal(int n) {
    // your code here
    if(n/1000==0){
        if(n%1000==0) return 0;
        else if(n%1000==1) return 1;
        else if(n%1000==10) return 2;
        else if(n%1000==11) return 3;
        else if(n%1000==100) return 4;
        else if(n%1000==101) return 5;
        else if(n%1000==110) return 6;
        else return 7;
    }
    else return binary2octal(n/1000)*10+binary2octal(n%1000);
}

int main(){
    int n;
    while (cin >> n){
        cout  << n << " is equivalent to " << binary2octal(n);
        cout  << " in base 8" << endl;
    }
}