Problem

Write a Java program Temp, that converts celcius to fahrenheit or vice versa.

Your program should do the following:

• prompt the user for a 1-character string c (celcius) or f (fahrenheit) that tells the program which unit you are entering
• prompt the user for the temperature
• output the solution followed by a c or f to denote the final units

Example: User inputs "c" and "10" would result in "50f"

Use the following formula to convert your units

F = 9C/5 + 32

Temperature Calculator

Solution

Start by importing the swing java package.

 import javax.swing.*;

Define your variables, we will need doubles in case of decimal results, and a string value for the unit

double temperature, result;
String unit;

Next start by capturing the user input using JOptionPane. We will need to use Integer.parseInt to cast the String result to an integer for the temperature.

unit = JOptionPane.showInputDialog("Enter the 1-character temperature you want to convert from c (Celcius) or f (Fahrenheit)") ;
temperature = Integer.parseInt(JOptionPane.showInputDialog("Enter the current temperature in the units you speficied"));

Now we need to use conditional statements to check for each unit, one for Celcius and one for Fahrenheit. One thing to note is that because unit is a String datatype, we will have to only extract the first character assuming it has be entered in correctly, this is easily accomplished using

unit.charAt(int index)

Where index is the position at which the char character is at in the String. For each case, calculate your results and print the output using System.out. To make your program more robust, you may want to use an else case for all invalid characters.

if (unit.charAt(0) == 'c')
{
	result = 9 * temperature / 5 + 32;
	System.out.println(temperature + " degree Celcius = " + result + " degree Fahrenheit");
}
else if (unit.charAt(0) == 'f')
{
	result = (temperature - 32) * 5 / 9;
	System.out.println(temperature + " degree Fahrenheit = " + result + " degree Celcius");
}
else
	System.out.printline("You entered an incorrect unit, please try again");

Code

Solution Code

import javax.swing.*;

public class  Temp
{

	public static void main(String[] args)
	{
		double temperature, result;
		String unit;
		unit = JOptionPane.showInputDialog("Enter the 1-character temperature you want to convert from c (Celcius) or f (Fahrenheit)") ;
		temperature = Integer.parseInt(JOptionPane.showInputDialog("Enter the current temperature in the units you speficied"));

		if (unit.charAt(0) == 'c')
		{
			result = 9 * temperature / 5 + 32;
			System.out.println(temperature + " degree Celcius = " + result + " degree Fahrenheit");
		}
		else if (unit.charAt(0) == 'f')
		{
			result = (temperature - 32) * 5 / 9;
			System.out.println(temperature + " degree Fahrenheit = " + result + " degree Celcius");
		}
		else
			System.out.printline("You entered an incorrect unit, please try again");

	}

}