#include <iostream>
#include <cmath>

using namespace std;

int convert;
int n;
int binary;
int num;
int convertBinaryToDecimal(long long);
int DecimalToBinary();
int octalToDecimal(int octalNumber);
int decimalToOctal(int decimalNumber);
int octalNumber;
int decimalNumber;
long long convertDecimalToBinary(int);
int binaryNumber;


int main ()
{


cout << "Choose the conversion method: \n" <<endl;
cout << "1. Binary to Decimal \n" << endl;
cout << "2. Decimal to Binary \n" << endl;
cout << "3. Octal to Decimal \n" << endl;
cout << "4. Decimal to Octal \n" << endl;

cout << "Please enter: " << endl;
cin >> convert;

if (convert==1)  // BINARY TO DECIMAL
{
    long long n;
    cout <<"You are now converting BINARY into DECIMAL" << endl;
    cout << "Please enter Binary:" << endl;
    cin >> n;

    cout << n << " is " << binaryNumber << " in DECIMAL";
    return 0;
} //CONVERT 1 END


if (convert==2) // DECIMAL TO BINARY (PROOOOOOOOOOOOOOOOOOOOOOBLEM)
{
    cout <<"You are now converting DECIMAL into BINARY" << endl;
    cout << "Please enter DECIMAL:" << endl;
    cin >> n;
    cout << n << " is " << convertDecimalToBinary(n) << " in BINARY";


}

if(convert==3) // OCTAL TO DECIMAL
{
    cout <<"You are now converting OCTAL into DECIMAL" << endl;
    cout << "Please enter OCTAL:" << endl;
    cin >> octalNumber;

    cout << octalNumber << " is " << octalToDecimal(octalNumber) << " in DECIMAL";
    return 0;
}

if(convert==4) //DECIMAL TO OCTAL
{
    cout <<"You are now converting DECIMAL into OCTAL" << endl;
    cout << "Please enter DECIMAL:" << endl;
    cin >> decimalNumber;

    cout << decimalNumber << " is " << decimalToOctal(decimalNumber) << " in OCTAL";
    return 0;
}
} // MAIN END


int convertBinaryToDecimal(long long n) // FORMULA FOR CONVERTING BINARY TO DECIMAL (1)
{
    int decimalNumber = 0, i = 0, remainder;
    while (n!=0)
    {
        remainder = n%10;
        n /= 10;
        decimalNumber += remainder*pow(2,i);
        ++i;
    }
    return decimalNumber;
}

long long convertDecimalToBinary(int n) //DECIMAL TO BINARY (2)
{
    long long binaryNumber = 0;
    int remainder, i = 1, step = 1;

    while (n!=0)
    {
        remainder = n%2;
        step++;
        n;
        remainder;
        n/2;
        n /= 2;
        binaryNumber += remainder*i;
        i *= 10;
    }
    return binaryNumber;
}

int octalToDecimal(int octalNumber) // FORMULA FOR CONVERTING OCTAL TO DECIMAL (3)
{
    int decimalNumber = 0;
    int i = 0;
    int rem;

    while (octalNumber != 0)
    {
        rem = octalNumber % 10;
        octalNumber /= 10;
        decimalNumber += rem * pow(8, i);
        ++i;
    }
    return decimalNumber;
}

int decimalToOctal(int decimalNumber) // FORMULA FOR CONVERTING DECIMAL TO OCTAL (4)
{
    int rem, i = 1, octalNumber = 0;
    while (decimalNumber != 0)
    {
        rem = decimalNumber % 8;
        decimalNumber /= 8;
        octalNumber += rem * i;
        i *= 10;
    }
    return octalNumber;
}