Java Program to Convert Binary To Decimal

Write a Java program to convert binary to decimal. We can use the parseInt with two as the second argument will convert the binary string to a decimal integer.

package Remaining;

public class BinaryToDecimal1 {
	
	public static void main(String[] args) {
		
		String s1 = "1101";
		String s2 = "10101";
		String s3 = "11111";
		String s4 = "110101";
		
		System.out.println(Integer.parseInt(s1, 2));
		System.out.println(Integer.parseInt(s2, 2));
		System.out.println(Integer.parseInt(s3, 2));
		System.out.println(Integer.parseInt(s4, 2));
	}
}

13
21
31
53

This example accepts the binary string and converts it to a decimal number.

package Remaining;

import java.util.Scanner;

public class BinaryToDecimal2 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		
		sc= new Scanner(System.in);

		System.out.print("Please Enter Binary Number =  ");
		String binaryString = sc.nextLine();
	
		int decimalVal = Integer.parseInt(binaryString, 2);
		System.out.println("Binary To Decimal Result = " + decimalVal);
	}
}

This program helps to convert binary to a decimal using a while loop. We have already explained the logic in c programs.

package Remaining;

import java.util.Scanner;

public class BinaryToDecimal3 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		
		int  binaryVal, temp, remainder, decimal = 0, n = 0;
		sc= new Scanner(System.in);

		System.out.print("Please Enter Number =  ");
		binaryVal = sc.nextInt();
		
		temp = binaryVal;
		
		while(temp > 0)
		{
			remainder = temp % 10;
			decimal = (int) (decimal + remainder * Math.pow(2, n));
			temp = temp / 10;
			n++;
		}

		System.out.println("Binary " + binaryVal + " To Decimal Result = " + decimal);
	}
}

Please Enter Number =  110011001
Binary 110011001 To Decimal Result = 409

Please Enter Number =  11111
Binary 11111 To Decimal Result = 31

The below program accepts the number and converts the binary value to a decimal number using functions.

package Remaining;

import java.util.Scanner;

public class BinaryToDecimal4 {
	private static Scanner sc;
	
	public static void main(String[] args) {

		sc= new Scanner(System.in);

		System.out.print("Please Enter Number =  ");
		int binaryVal = sc.nextInt();
		
		int decimal = binaryToDecimal(binaryVal);

		System.out.println("Result = " + decimal);
	}
	
	public static int binaryToDecimal(int binaryVal)
	{
		int remainder, decimal = 0, base = 1;
		
		while(binaryVal > 0)
		{
			remainder = binaryVal % 10;
			decimal = decimal + (remainder * base);
			binaryVal = binaryVal / 10;
			base = base * 2;
		}
		return decimal;
	}
}

Please Enter Number =  11011010
Result = 218

Please Enter Number =  1111111
Result = 127