Program to Convert Decimal to Binary Number - C, C++ Code with Examples

Write a C, C++ program to convert a decimal number to binary number. In this program, Our code take a decimal number as an input from a user and convert them into a binary number.

Program to Convert Decimal to Binary Number

Basic Programs for Practice

Program to convert binary to decimal number

How to Convert Decimal to Binary Number

1. Take an input from a user.

2. Check whether a number is greater than zero.

3. Run a loop until the number is greater than zero.

a: Divide the original decimal number by 2 and store it's remainder.
b: Increment i and array subscript.

          while(num > 0){
             arr[i] = num%2;
             i++;
             num = num/2;
          } 

4. Print the array in a reverse order.

Program to Convert Binary to Decimal Number


Let's convert 3 into binary


Step 1:  3 / 2  Remainder : 1 , Quotient : 1
Step 2:  1 / 2  Remainder : 1 , Quotient : 0

So Binary Conversion of 2 is 11

Let's convert 12 into binary

Step 1:   12/ 2  Remainder : 0 , Quotient : 6
Step 2:   6 / 2  Remainder : 0 , Quotient : 3
Step 4:   3 / 2  Remainder : 1 , Quotient : 1
Step 5:   1 / 2  Remainder : 1 , Quotient : 0

So Binary Conversion of 12 is 1100

C Program to Convert Decimal to Binary Number

#include<stdio.h>

void main(){

    int arr[10],i=0,num,j;

    printf("Enter decimal number \n");
    scanf("%d",&num);
       
    /* If a number is greater than zero. */

     while(num > 0){
            
        /* store the remainder of a number in array. */

         arr[i] = num%2;
         i++;
         num = num/2;
     } 

    /* Print the array(arr) in reverse order.*/

    printf("Binary representation of an input number is\n");
 
    for(j=i-1; j>=0; j--){
         printf("%d",arr[j]);
    } 

}

C++ Program to Convert Decimal to Binary Number

#include <iostream>

using namespace std;

int main() {
    
    int num, i = 0, arr[20];
 
    cout << "Enter a number\n";
    cin  >> num;
    
    int temp = num;
    
    //While temp is greater than 0
    while (temp > 0) {

       //store remainder in an array
       arr[i++] = temp%2;

       //divide a number by 2 in each iteration
       temp  = temp / 2;
    }
 
    cout <<"Binary representation of " << num << " is \n"; 
 
    //Print an array in a reverse order
    for(int j = i-1; j >= 0; j--) {
        cout << arr[j] << " ";
    }
 
    return 0;
}

Output -

Enter a number
12

Binary representation of 12 is   1 1 0 0

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