#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int binaryToOctal(long long bin)
{
    int oct = 0, dec = 0, i = 0;

    // converting binary to decimal
    while (bin != 0)
    {
        dec += (bin % 10) * pow(2, i);
        ++i;
        bin /= 10;
    }
    i = 1;

    // converting to decimal to octal
    while (dec != 0)
    {
        oct += (dec % 8) * i;
        dec /= 8;
        i *= 10;
    }
    return oct;
}

long long octalToBinary(int oct)
{
    int dec = 0, i = 0;
    long long bin = 0;

    // converting octal to decimal
    while (oct != 0)
    {
        dec += (oct % 10) * pow(8, i);
        ++i;
        oct /= 10;
    }
    i = 1;

    // converting decimal to binary
    while (dec != 0)
    {
        bin += (dec % 2) * i;
        dec /= 2;
        i *= 10;
    }
    return bin;
}

int main()
{
    int operation;
    int octal;
    long long int binary;
    printf("-----Select the Operation------\n");
    printf("1. Binary to Octal\n2. Octal to Binary\n3. Exit\n");
    printf("Enter the corresponding number of Operation: ");
    scanf("%d", &operation);

    switch (operation)
    {
    case 1:
        printf("Enter a binary number: ");
        scanf("%lld", &binary);
        printf("%lld in binary = %d in octal", binary, binaryToOctal(binary));
        break;

    case 2:
        printf("Enter an octal number: ");
        scanf("%d", &octal);
        printf("%d in octal = %lld in binary", octal, octalToBinary(octal));
        break;

    case 3:
        exit(0);

    default:
        printf("Wrong input");
    }

    return 0;
}