Example: C program to convert octal Number to binary number

C
C++
C#
Java
Python
PHP
// C program to convert octal Number to binary number
#include <stdio.h>
#include <math.h>

// It's main function of the program
int main() {
    int decimal_num, octal_num, temp_octal_num, i = 0;
    long long binary_num;

    printf("Enter Octal Number: ");
    scanf("%d", &temp_octal_num);
    octal_num = temp_octal_num;

    // Step-1 make conversion octal to decimal
    while (temp_octal_num != 0) {
        decimal_num += (temp_octal_num % 10) * pow(8, i);
        ++i;
        temp_octal_num /= 10;
    }
    i = 1;

    // Step-2 then make conversion decimal to binary
    while (decimal_num != 0) {
        binary_num += (decimal_num % 2) * i;
        decimal_num /= 2;
        i *= 10;
    }

    // Final output of the program
    printf("\n%d (Octal Number) = %lld (Binary Number)\n", octal_num, binary_num);
    return 0;
}