Question

The following table shows the approximate speed of sound in air, water, and steel:

Medium	Speed
Air	1,100 feet per second
Water	4,900 feet per second
Steel	16,400 feet per second

Write a program that asks the user to enter “air”, “water”, or “steel”, and the distance that a sound wave will travel in the medium. The program should then display the amount of time it will take. You can calculate the amount of time it takes sound to travel in air with the following formula:

Time=Distance/1,100Time=Distance/1,100

You can calculate the amount of time it takes sound to travel in water with the following formula:

Time=Distance/4,900Time=Distance/4,900

You can calculate the amount of time it takes sound to travel in steel with the following formula:

Time=Distance/16,400

This is the question Below is what I wrote but I need the program to have these certain things

• The user can enter upper or lower case letters

• the user needs to be told if they enter an incorrect medium

• the user needs to be told if they enter an amount of time that is less than 0

• display time in seconds to 2 decimal places

package speedofsound;
import java.util.Scanner;

public class SpeedofSound {

public static void main(String[] args)
{
//Variables
double distance;
double time;
String input;
Scanner keyboard = new Scanner (System.in);
  
//Ask user for air, water, or steel
System.out.print("Enter air, water, or steel: ");
input = keyboard.nextLine();
//Ask user for distance
System.out.print("Enter distance: ");
distance = keyboard.nextDouble();
  
//while (distance >0 )
  
//System.out.println("Please enter a number greater then 0");
  
//Add if statement
if (input.equals("air"))
{ time = (distance / 1100);
System.out.println("The total time traveled is " + time + ".");
}
else if (input.equals("water"))
{ time = (distance / 4900);
System.out.println("The total time traveled is " + time + ".");
}
else if (input.equals("steel"))
{ time = (distance / 16400);
System.out.println("The total time traveled is " + time + ".");
}
}
  
}

Answer 1

import java.util.Scanner;

public class SpeedofSound {

   public static void main(String[] args) {
//Variables
       double distance;
       double time;
       String input;
       Scanner keyboard = new Scanner(System.in);

//Ask user for air, water, or steel
       System.out.print("Enter air, water, or steel: ");
       input = keyboard.nextLine();
//Ask user for distance
       System.out.print("Enter distance: ");
       distance = keyboard.nextDouble();

//while (distance >0 )
       // adding validation if user gives distance as <0
       while (distance < 0) {
           System.out.println("Please enter a number greater then 0");
           System.out.print("Enter distance: ");
           distance = keyboard.nextDouble();
       }

//Add if statement with equalsIgnoreCase
       if (input.equalsIgnoreCase("air")) {
           time = (distance / 1100);
           System.out.printf("The total time traveled is %.2f.", time);
       } else if (input.equalsIgnoreCase("water")) {
           time = (distance / 4900);
           System.out.printf("The total time traveled is %.2f.", time);
       } else if (input.equalsIgnoreCase("steel")) {
           time = (distance / 16400);
           System.out.printf("The total time traveled is %.2f.", time);
       } else {
           System.out.println("Invalid medium");
       }
   }

}