Thread: Switch

Hey guys working on a simple switch program but not exactly a 100% if i can convert my what was a if statement into a switch or not. Any help would be awesome Thanks!

import java.util.Scanner;
 
public class math
{
  public static void main(String[] args)
{
 
 
Scanner input = new Scanner(System.in);
 
System.out.println(" Please select one of these options.");    
System.out.println(" 1. Press A to add three numbers ");
System.out.println(" 2. Press S to subtract two numbers ");
System.out.println(" 3. Press M to multiply by three numbers ");
System.out.println(" 4. Press D to divide by two numbers ");
System.out.println(" 5. Press O to modulus two numbers ");
System.out.println(" 6. Press E to quit the program ");
System.out.println(" ");
 
int option= input.nextInt();
 
 
    switch (option)
    {
    case 'A': {
      addition (); }
    break;
      case 'S': {
      subtract (); }
      break;
    case 'M': {
      multiply (); }
    break;
      case 'D': {
      divide (); }
      break;
      case 'O': {
      modulus (); }
      break;
      case 'E': {
      quit ();}
      break;
      default: 
 
      System.out.println("Not a option"); }
 
    }
 
 
    public static void addition(){
             Scanner input = new Scanner( System.in );
             float number1;
             float number2;
             float number3;
             float sum;
 
      System.out.printf( "Enter first integer: " );
      number1 = input.nextInt();
      System.out.printf( "Enter second integer: " );
      number2 = input.nextInt();
      System.out.printf( "Enter Third integer: " );
      number3 = input.nextInt();
 
             sum = number1 + number2 + number3;
             System.out.printf( "Sum equals %f\n", sum);
    }
    public static void subtract(){
             Scanner input = new Scanner( System.in );
             float number1;
             float number2;
             float difference;
 
      System.out.printf( "Enter number to be subtracted: " );
      number1 = input.nextInt();
      System.out.printf( "Enter integer to subtract: " );
      number2 = input.nextInt();
 
 
             difference = number1 - number2;
             System.out.printf( "The difference is %f\n", difference);
 
    }
    public static void multiply(){
            Scanner input = new Scanner( System.in );
             float number1;
             float number2;
             float number3;
             float product;
 
      System.out.printf( "Enter first integer to multiply: " );
      number1 = input.nextInt();
      System.out.printf( "Enter second integer: " );
      number2 = input.nextInt();
      System.out.printf( "Enter Third integer: " );
      number3 = input.nextInt();
 
      product = number1 * number2 * number3;
      System.out.printf( "The product is %f\n", product);
 
    }
 
    public static void divide(){
          Scanner input = new Scanner( System.in );
           float number1;
           float number2;
           float dividen;
 
      System.out.printf( "Enter first integer: " );
      number1 = input.nextInt();
      System.out.printf( "Enter second integer: " );
      number2 = input.nextInt();
 
      dividen = number1 / number2;
      System.out.printf( "The dividen equals %f\n", dividen);
 
    }
 
    public static void modulus(){
         Scanner input = new Scanner ( System.in );
          float number1;
          float number2;
          float sum;
 
        System.out.printf( "Enter first integer: " );
        number1 = input.nextInt();
        System.out.printf( "Enter second ineger: " );
        number2 = input.nextInt();
 
        sum = number1 % number2;
        System.out.printf( "The answer equals %f\n", sum);
 
    }
 
    public static void quit(){
      System.out.printf( "Thank you for trying to use the program.");
      return; 
 
    }
 
  }

Can you explain what the problem is?

The message printed for the default: should include the invalid option's value.

java.util.InputMismatchException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at question4.main(question4.java:21)

The call to nextInt() at line 21 is trying to read an int value from the keyboard but the user is entering something that is not a numeric value. Use the next() or nextLine() method if you want to read a String not a number.

To convert an int to a String just use Integer.parseInt(number)

Wrong. The parseInt() method converts a String to an int.
Read the String class's API doc for methods to convert an int to a String.

With Java 1.7 switch statements will work with Strings.