binary2octal

#include<bits/stdc++.h>
using namespace std;
#define sz(x) int(x.size())
#define nl "\n"


void binToOctal(){

    string num ;
    cout << "Enter the number in binary to convert it to octal : ";
    cin >> num;


    map < string , int > mp;    // store the first 3 digit to equal it  in decimal
    mp["000"]=0 , mp["001"]=1 , mp["010"]=2 , mp["011"]=3,
    mp["100"]=4 , mp["101"] =5 , mp["110"]= 6, mp["111"] =7;

    int idx =-1;
    for(int i = 0; i < num.size() ; i++){
        if(num[i]=='.'){
            idx = i;
            break;
        }
    }

        string temp; // contain the part before floating point

        if(idx ==-1) // no floating point
             temp = num ;
        else
            temp = num.substr(0 , idx);


        string ans="";

        int mod = int(temp.size()) % 3;
        if(mod){
            mod = 3- mod;
            while(mod--) ans+='0';
        }

        ans+= temp;

        string result ="";
        for(int i=0 ; i < ans.size() ; i+=3){
            string st = ans.substr(i , 3);
            result+= '0'+ mp[st];
        }

   if(idx!=-1){ // contain floating point

        result+='.';

        string point= num.substr(idx+1);

        int mod2= int (point.size())% 3 ;
        if(mod2){
            mod2= 3- mod2 ;
            while(mod2--) point +='0';
        }

        for(int i=0 ; i < point.size() ; i+=3){
            string st2 = point.substr(i , 3);
            result+= '0'+ mp[st2];
        }
    }

    cout <<"octal number : " << result << nl;

}
int main() {


    binToOctal();

    return 0;
}