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C program to convert a binary number to an octal number

Here, we are going to learn how to convert a binary number to an octal number in C programming language?
Submitted by Nidhi, on July 03, 2021

Problem statement

Here, we will read a number in binary format (0s and 1s) from the user and convert it to an octal number, and print it on the console screen.

C program to convert a binary number to an octal number

The source code to convert a binary number to an octal number is given below. The given program is compiled and executed using GCC compile on UBUNTU 18.04 OS successfully.

// C Program to convert a binary number to octal number

#include <stdio.h>

int main()
{
    int binaryNumber = 0;
    int octalNumber = 0;
    int i = 1;
    int rem = 0;

    printf("Enter binary number: ");
    scanf("%d", &binaryNumber);

    while (binaryNumber != 0) {
        rem = binaryNumber % 10;
        octalNumber = octalNumber + rem * i;

        i = i * 2;
        binaryNumber = binaryNumber / 10;
    }

    printf("Octal Number: %o", octalNumber);
    return 0;
}

Output

Enter binary number: 1011
Octal Number: 13

Explanation

Here, we created 4 integer variables binaryNumber, octalNumber, i, rem that are initialized with 0. Then we read a number in binary format (1s and 0s). Then we converted the number into a decimal number and printed the corresponding octal number using the "%o" format specifier on the console screen.

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