# C# program to convert a decimal number into a binary number

Here, we are going to learn how to convert a decimal number into a binary number in C#?
Submitted by Nidhi, on September 12, 2020

Here we will read a decimal number and then convert it into a corresponding binary number.

Program:

The source code to convert a decimal number to the binary number is given below. The given program is compiled and executed successfully on Microsoft Visual Studio.

```//C# program to convert a decimal number to the binary number

using System;

class Program
{
static void Main(string[] args)
{
int decNum  =   0;
int binNum  =   0;

string tempRem = "";

Console.Write("Enter a decimal number : ");

while (decNum >= 1)
{
tempRem += (decNum % 2).ToString();
decNum = decNum / 2;
}

for (int i = tempRem.Length - 1; i >= 0; i--)
{
binNum = binNum*10 + tempRem[i]-0x30;
}

Console.WriteLine("Binary Number: "+binNum);
}
}
```

Output:

```Enter a decimal number : 9
Binary Number: 1001
Press any key to continue . . .
```

Explanation:

In the above program, we create a class Program that contains the Main() method, In the Main() method we read a decimal number from user input and then convert the decimal number into a corresponding binary number.

```while (decNum >= 1)
{
tempRem += (decNum % 2).ToString();
decNum = decNum / 2;
}
```

In the above code, we find the remainder of the decimal number after dividing by 2 and then concatenated into the string.

```for (int i = tempRem.Length - 1; i >= 0; i--)
{
binNum = binNum*10 + tempRem[i]-0x30;
}
```

In the above code, we reversed the remainder string and covert the into the integer number and then print the result on the console screen.