C program to convert Decimal to Octal number system

Write a C program to input decimal number from user and convert to octal number system. How to convert from decimal number system to octal number system in C programming. Logic to convert decimal to octal number system in C programming.

Example

Input

Input decimal: 22

Output

Octal number: 26

Required knowledge

Basic C programming, While loop

Decimal number system

Decimal number system is a base 10 number system. Decimal number system uses 10 symbols to represent all numbers i.e. 0123456789.

Octal number system

Octal number system is a base 8 number system. Octal number system uses 8 symbols to represent all numbers i.e. 01234567

Algorithm to convert decimal to octal

Algorithm Decimal to Octal conversion
    begin:
        read(decimal);
        octal ← 0; place ← 1; rem ← 0;
        While (decimal > 0) do
            begin:
                remdecimal % 8;
                octal ← (rem * place) + octal;
                placeplace * 10;
                decimaldecimal / 8;
            end;
        print('Octal number' octal);
    end;

Program to convert decimal to octal number system

/**
 * C program to convert from Decimal to Octal number system
 */

#include <stdio.h>

int main()
{
    long long decimal, tempDecimal, octal;
    int i, rem, place = 1;

    octal = 0;

    /* Input decimal number from user */
    printf("Enter any decimal number: ");
    scanf("%lld", &decimal);

    tempDecimal = decimal;

    /* Decimal to octal conversion */
    while(tempDecimal > 0)
    {
        rem = tempDecimal % 8;

        octal = (rem * place) + octal;

        tempDecimal /= 8;

        place *= 10;
    }

    printf("\nDecimal number = %lld\n", decimal);
    printf("Octal number = %lld", octal);

    return 0;
}

Output

Enter any decimal number: 20
Decimal number = 20
Octal number = 24

Happy coding 😉

About Pankaj

Pankaj Prakash is the founder, editor and blogger at Codeforwin. He loves to learn new techs and write programming articles especially for beginners. He works at Vasudhaika Software Sols. as a Software Design Engineer and manages Codeforwin. In short Pankaj is Web developer, Blogger, Learner, Tech and Music lover.

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