C++ Program to convert Decimal to Binary

We can convert any decimal number (base-10 (0 to 9)) into binary number (base-2 (0 or 1)) by C++ program.

Decimal Number

Decimal number is a base 10 number because it ranges from 0 to 9, there are total 10 digits between 0 to 9. Any combination of digits is decimal number such as 223, 585, 192, 0, 7 etc.

Binary Number

Binary number is a base 2 number because it is either 0 or 1. Any combination of 0 and 1 is binary number such as 1001, 101, 11111, 101010 etc.

Let's see the some binary numbers for the decimal number.

Decimal	Binary
1	0
2	10
3	11
4	100
5	101
6	110
7	111
8	1000
9	1001
10	1010

Decimal to Binary Conversion Algorithm

Step 1: Divide the number by 2 through % (modulus operator) and store the remainder in array

Step 2: Divide the number by 2 through / (division operator)

Step 3: Repeat the step 2 until the number is greater than zero

Let's see the C++ example to convert decimal to binary.

#include <iostream>  
using namespace std;  
int main()  
{  
  int a[10], n, i;    
  cout<<"Enter the number to convert: ";    
  cin>>n;    
  for(i=0; n>0; i++)    
 {    
   a[i]=n%2;    
   n= n/2;  
  }    
 cout<<"Binary of the given number= ";    
 for(i=i-1 ;i>=0 ;i--)    
 {    
   cout<<a[i];    
 }    
}

Output:

Enter the number to convert: 9

Binary of the given number= 1001