C programming, Transform binary numbers into octal format and convert them back to binary.

#include <math.h>

#include <stdio.h>

int convert(long long bin);

int main() {

    long long bin;

    printf("Enter a binary number: ");

    scanf("%lld", &bin);

    printf("%lld in binary = %d in octal", bin, convert(bin));

    return 0;

}

int convert(long long bin) {

    int oct = 0, dec = 0, i = 0;

    while (bin != 0) {

        dec += (bin % 10) * pow(2, i);

        ++i;

        bin /= 10;

    }

    i = 1;

    while (dec != 0) {

        oct += (dec % 8) * i;

        dec /= 8;

        i *= 10;

    }

    return oct;

}