Question

(NumberFormatException)Write the bin2Dec(String binaryString) method to convert a binary string into a decimal number. Implement the bin2Dec method to throw a NumberFormatException if the string is not a binary string. Write a test program that prompts the user to enter a binary number as a string and displays decimal equivalent of the string. If the method throws an exception, display "Not a binary number".Sample Run 1Enter a binary number: 1015Sample Run 2Enter a binary number: 41Not a binary number: 41Class Name: Exercise12_07

Answer 1

The following program will be used that prompts the user to enter a binary number as a string and displays decimal equivalent of the string.

Explanation:

NumberFormat.java

import java.util.Scanner;

public class NumberFormat{

public static void main(String[] args) {

      Scanner scan = new Scanner(System.in);

      try{

      System.out.println("Enter a binary string:");

      String s = scan.next();

      int integerValue = bin2Dec(Integer.parseInt(s));

      System.out.println("The decimal value of "+s+" is "+integerValue);

      }

      catch(NumberFormatException e){

          System.out.println(e);

      }

  }  

  public static int bin2Dec(int binaryNumber) throws NumberFormatException{

  int decimal = 0;

  int p = 0;

  try{

  while(true){

  if(binaryNumber == 0){

  break;

  } else {

  int temp = binaryNumber%10;

  decimal += temp*Math.pow(2, p);

  binaryNumber = binaryNumber/10;

  p++;

  }

  }

  }

  catch(NumberFormatException e){

      throw new NumberFormatException("Invalid binary number");

  }

  return decimal;

  }

}

Output:

Enter a binary string:

1011000101

The decimal value of 1011000101 is 709