java only please.... The switch statement in Java allows for multi-way branching

ID: 3857839 • Letter: J

Question

java only please....

The switch statement in Java allows for multi-way branching in an easy to read and easy to write format. The switch statement has many restrictions on when and how it can be used. The sytnax is as follows:

switch(variable or expression goes here)
{
case XXX: a possible value the variable may hold: statements to execute when the
                   variable holds the value
                   optional break;
case XXX: a possible value the variable may hold: statements to execute when the
                  variable holds the value
                  optional break;
case XXX: possible value the variable may hold: statements to execute when the
                  variable holds the value
              optional break;
optional default: statements to execute if the variable did not match the value in
                               any of the cases
}

Here is an example to read and use as a reference.
char choice;
System.put.print( “Enter your choice, A, B, C, or D: “)
choice input.next( ).charAt(0);

switch (choice)
{
   case ‘A’: System.out.println( “You chose A for Apple! “);
                  break;
   case ‘B’: System.out.println( “You chose B for Banana!”);
                   break;
   case ‘C’: System.out.println( “You chose C for Candy!”);
                 break;
   case ‘D’: System.out.println(“You chose D for Donuts!”);
              break;
      default: System.out.println(“You did not pick a valid choice!”)
} //end of switch

  The expression in the switch condition must be of type int or char ( or String with Java 8).

Each of the case labels (like ‘A’, ‘B’…) must be either hard coded or symbolic constants, they cannot be variables.

You can put as many statements as you need in each case.

The default case is optional.

After you have read the code above write a program that asks the user to enter 2 floating point numbers and a character * / % + or – Then use a switch statement to perform the operation on the two floating point numbers and print the answer after performing that operation.

If the user enters a 0 for a denominator (second input number) when choosing /, print a message stating that it is not possible to divide by 0.

Part B: Create a Java project. Name this project 5B

You must use a switch statement in this next program: Write a program that asks the user to enter two integers. The first is the month and the second integer is the day in the month. Then calculate and print how many days have passed in the year. If the user enters a date that cannot be in the month they specified, print an error message. If the user enters a month other than 1 to 12, print an error message.

Use the following piece of code to help you get started.

int totalDays = 0;

switch(month)
{ case 1:   if(day > 31 || day < 0)
                 {
                      System.out.println(“Your day of month is invalid”;

}

else { totalDays = day; }

break;

Explanation / Answer

SwitchTester1.java

import java.util.Scanner;

public class SwitchTester1 {

public static void main(String [] args){

Scanner scan = new Scanner(System.in);

//asks the user to enter 2 floating point numbers and a character * / % + or –

System.out.println("Please enter 2 floating point numbers and a character * / % + or –");

Float fl1 = Float.valueOf(scan.nextLine());

Float fl2 = Float.valueOf(scan.nextLine());

String operator = scan.nextLine();

double sub=0;

//use a switch statement to perform the operation on the two floating point numbers

//and print the answer after performing that operation.

switch(operator){

case "*" : System.out.println(fl1 +" * "+ fl2+" = "+fl1*fl2);

break;

case "/" : if(fl2 == 0){

// If the user enters a 0 for a denominator (second input number) when choosing /,

// print a message stating that it is not possible to divide by 0.

System.out.println("not possible to divide by 0.");

}

else{

System.out.println(fl1 +" / "+ fl2+" = "+fl1/fl2);

}

break;

case "%" : System.out.println(fl1 +" % "+ fl2+" = "+fl1%fl2);

break;

case "+" : System.out.println(fl1 +" + "+ fl2+" = "+fl1+fl2);

break;

case "-" : sub= fl1.floatValue() - fl2.floatValue();

System.out.println(fl1 +" - "+ fl2+" = "+sub);

break;

default : System.out.println("Invalid option!");

}

Sample output:

Please enter 2 floating point numbers and a character * / % + or –
5.0
3.0
-
5.0 - 3.0 = 2.0

SwitchTester2.java

import java.util.Scanner;

public class SwitchTester2 {

public static void main(String [] args){

Scanner scan = new Scanner(System.in);

//asks the user to enter two integers.

//The first is the month and the second integer is the day in the month

System.out.println("Please enter month and date: ");

int month = Integer.valueOf(scan.nextLine());

int day = Integer.valueOf(scan.nextLine());

int totalDays = 0;

switch(month)

{

case 1: if(day > 31 || day < 0)

{