C# program to convert decimal to binary:
This post will show you how to convert a decimal value to binary in C#. Decimal number system is base 10 number system and binary number system is base 2 number system. The program will take a decimal number as input from the user and it will convert and it will convert it to binary and print it to the user.
Decimal number system:
Decimal is a base 10 number system. It uses 10 different digits to represent a number: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. It is the most popular number system.
Binary number system:
Binary is a base 2 number system. It uses 1 and 0 to represent a number in binary. Each digit is known as bit in binary.
To convert a decimal value to binary, we will follow the following algorithm:
Algorithm to convert Decimal to Binary:
- Divide the number by 2 and keep the remainder in an array.
- Change the number to the quotient.
- Keep dividing the number by 2 until the number is greater than 0.
- Print the content of the array in reverse.
For example, if we want to convert 21 to binary, we will have to follow the following steps:
- 21/2, remainder is 1, quotient is 10, add it to the array [1]
- Number is changed to 10. 10/2, remainder is 0, quotient is 5, add it to the array [1,0]
- Number is changed to 5. 5/2, remainder is 1, quotient is 2, add it to the array [1,0,1]
- Number is changed to 2. 2/2, remainder is 0, quotient is 1, add it to the array [1,0,1,0]
- Number is changed to 1. 1/2, remainder is 1, quotient is 0, add it to the array [1,0,1,0,1]
Now, the reverse of the array content is 10101, which is the binary value of 21.
Method 1: C# program with an array:
The below C# program uses the above algorithm to convert a decimal value to binary.
using System;
using System.Text;
namespace Program
{
class Program
{
static String getBinaryString(int d)
{
int[] arr = new int[20];
int i = 0;
StringBuilder binaryBuilder = new StringBuilder();
while (d > 0)
{
arr[i] = d % 2;
d = d / 2;
i++;
}
i--;
while (i >= 0)
{
binaryBuilder.Append(arr[i]);
i--;
}
return binaryBuilder.ToString();
}
static void Main(string[] args)
{
int no;
Console.WriteLine("Enter the decimal number:");
no = int.Parse(Console.ReadLine());
Console.WriteLine("Binary: " + getBinaryString(no));
}
}
}Here,
- getBinaryString method is used to convert a decimal value to binary. It takes the decimal value as the parameter and returns the binary value of that number as string.
- It creates an array arr to hold the binary value. binaryBuilder is a StringBuilder object to create the final string.
- The first while loop finds the remainders and appends them to the array.
- The second while loop iterates through this array in reverse order and appends these values to the StringBuilder.
- It returns the string value of the StringBuilder object.
If you run this program, it will give output as like below:
Enter the decimal number:
21
Binary: 10101
Enter the decimal number:
19
Binary: 10011Method 2: Without using an array to hold the values:
We can also remove the array to hold the remainder values. Without using the array, we can add the remainder to the start of the StringBuilder. The StringBuilder class provides a method called Insert that takes the index position as the first parameter and adds a string to a specific index.
In the below program, we are using only a StringBuilder to create the final binary string:
using System;
using System.Text;
namespace Program
{
class Program
{
static String getBinaryString(int d)
{
int i = 0, remainder;
StringBuilder binaryBuilder = new StringBuilder();
while (d > 0)
{
remainder = d % 2;
binaryBuilder.Insert(0, remainder.ToString());
d = d / 2;
i++;
}
return binaryBuilder.ToString();
}
static void Main(string[] args)
{
int no;
Console.WriteLine("Enter the decimal number:");
no = int.Parse(Console.ReadLine());
Console.WriteLine("Binary: " + getBinaryString(no));
}
}
}One more advantage of this approach is that we removed the second while loop. It will be faster than the previous one.
It will give similar output.
Method 3: Recursive way:
This is another way to convert a decimal value to binary in C#. A recursive method calls itself again and again to find the final result. We can write a recursive method to get the binary value for a decimal number.
using System;
using System.Text;
namespace Program
{
class Program
{
static String getBinaryString(int d)
{
if (d < 2) return d.ToString();
int divisor = d / 2;
int remainder = d % 2;
return getBinaryString(divisor) + remainder;
}
static void Main(string[] args)
{
int no;
Console.WriteLine("Enter the decimal number:");
no = int.Parse(Console.ReadLine());
Console.WriteLine("Binary: " + getBinaryString(no));
}
}
}getBinaryString is changed to a recursive method. It will give similar result.
Method 4: By using Convert.ToString:
Convert.ToString method is the easiest way to covert a decimal value to any other base. This method is defined as like below:
public static string ToString (short value, int toBase);
public static string ToString (long value, int toBase);We can convert a 32 bit or 64 bit integer to another base string value. The base can be 2, 8, 10 or 16. For binary, we must provide 2.
using System;
namespace Program
{
class Program
{
static void Main(string[] args)
{
int no;
Console.WriteLine("Enter the decimal number:");
no = int.Parse(Console.ReadLine());
Console.WriteLine("Binary: " + Convert.ToString(no, 2));
}
}
}It will give similar output.
Enter the decimal number:
19
Binary: 10011You might also like:
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