C Program to Convert Decimal Number into Binary

In this tutorial, we will learn to write a program in c to convert a decimal number into a binary number. Here we will use the division concept to convert it into a binary number.

Before moving towards the writing program let’s know about the binary numbers.

What is the Binary Number?

binary number is a number that is expressed in the base-2 numeral system. This expression contains only numbers 0 and 1.

For eg:

If we want to write decimal in binary

1 can be written as 0 0 0 1 = 2^0

2 can be written as 0 0 1 0 = 2^1

3 can be written as 0 0 1 1 = 2^1 + 2^0

4 can be written as 0 1 0 0 = 2^2

How our binary number conversion program will behave?

  • Binary number conversion program in C will take decimal as an input.
  • We will divide the number by 2 to find the remainder and store that remainder.
  • After storing reminder replace the original number with the new number which we got after divided by two.
  • This process will continue till original number become 0.
  • Here remaindar is binary number which we will get everytime.

C Program to convert decimal number into binary

#include <stdio.h>
int main()
    int arr[10], num, i, j;
    printf("Program to Convert Decimal Number into Binary\n");
    printf("Please Give a Number to Convert in Binary:  ");
    scanf("%d", &num);
    printf("Binary Number of %d is =  ",num);
    for(i = 0; num > 0; i++)
        arr[i] = num % 2;
        num = num / 2;
    for(j = i - 1; j >= 0; j--)  {
        printf(" %d ", arr[j]);
    return 0;


C Program to Convert Decimal Number into Binary

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