Thread: (Beginner) Hopelessly lost on Temperature converting (C to F, F to C)

4 Hours of struggles, no result..Completely stuck with my dull brain and need help..

import java.util.Scanner;
 
public class Project5 {
 
	public static void main(String[] args) {
		Scanner keyboard = new Scanner(System.in);	
 
		double temp;
		System.out.print("Enter a temperature in degrees: ");
		temp = keyboard.nextDouble();
 
		System.out.print("Enter either letter C or F to indicate degrees Celsius or Fahrenheit, respectively: ");
		String s1 = keyboard.nextLine();
		String s2 = keyboard.nextLine();
 
 
		double Degrees_C = temp;
		double Degrees_F = temp;
 
		String c = s1;
		String C= s1;
		String F=s2;
		String f=s2;
 
		if (s1.equals(s1)) {
			Degrees_F = (9 * ((Degrees_C) / 5) + 32);
			System.out.print(temp + " degrees Fahrenheit is " + Degrees_F + " degrees Celsius.");}
		else if (s2.equals(s2)){
			Degrees_C = (5 * (Degrees_F - 32) / 9);
			System.out.print(temp + " degrees Celsius is " + Degrees_C + " degrees Fahrenheit.");}
		else	{
			System.out.print("You either entered the wrong value or did not enter a letter C nor F.");}
	}
}

It actually shows C to F really well.

The problems that I'm facing is that:
1. It doesn't convert F to C (Shows the C to F instead).
2. It doesn't display the error message when entering any letters other than C, c, f, or F. (EDIT) I don't think my code can read alphabet..
3. There can be too much decimal place...Any way to limit how far the decimal could go?

Thank you very much.

It doesn't convert F to C (Shows the C to F instead).

Is that a logic problem? How does the user tell the program which way to convert?

You need to walk through your logic using a piece of paper and a pencil. Make a box for each variable that you are using.
Go through your code, line by line and write in the box for each variable the value of each variable as it changes.
Look at each if statement and consider what the values of the variables are for that if statement.

There are six String variables. What are each of the variables used for?

way to limit how far the decimal

Look at the printf method or the DecimalFormat class to control the number of digits displayed.

dlorde & Norm, I can't thank you enough for your patience and contributions to the forums.

I can understand your frustrations when it comes to newbies and going over the same stuff again and again.
Feel free to take a back seat before you succumb to extreme stress lol

I can't be responsible for any nervous breakdowns

import java.util.Scanner;
 
public class Project5 {
 
	public static void main(String[] args) {
		Scanner keyboard = new Scanner(System.in);	
 
		double temp;
		System.out.print("Enter a temperature in degrees: ");
		temp = keyboard.nextDouble();
 
 
 
		double Degrees_C = temp;
		double Degrees_F = temp;
 
		System.out.print("Enter either letter C or F to indicate degrees Celsius or Fahrenheit, respectively: ");
		String s1 = keyboard.next();
		char c1 = s1.charAt(0);
 
		switch (c1){
			case 'C':
			case 'c':
			Degrees_F = (9 * ((Degrees_C) / 5) + 32);
			System.out.print(temp + " degrees Celsius is " + Degrees_F + " degrees Fahrenheit.");
			break; 
 
			case 'F':
			case 'f':
			Degrees_C = (5 * (Degrees_F - 32) / 9);
			System.out.print(temp + " degrees Fahrenheit is " + Degrees_C + " degrees Celsius.");
			break;
 
			default:
			System.out.print("You did not enter a letter C nor F.");
			break;
		}
	}
}

Finally got it...Actually Norm has helped me with his 2nd post, you know, a good-ol' piece of paper and pencil method So I retraced my steps, and realized that I was thinking too hard using if-else statements. So I researched a bit (since my textbook is a bit confusing), and found out there was a switch statement!!! And that charAt and resulting IndexOutofBoundsException kinda bothered me, but was able to solve it!

Some of you may be laughing right now at my newb excitement, but as all of you would know when you struggle at something for hours and find the solution (pretty much by yourself), it's really rewarding.

Also, plz don't hate or belittle (which is kinda how I felt) newbs... We are not trying to bother you guys, nor are we (at least I) expecting actual lines of coding. We know many of you're busy...I don't know about everyone else, but I only ask as a last resort...so maybe you non-newbs can kinda be that guiding light on solving a program that I can't solve.

I feel much satisfied solving a problem rather than others solving it for me. But since I probably am the most impatient person you'll ever encounter, there's a point (around 3 hour mark) that I go absolutely berserk. That's when I put my Q's on the forum. If you do give me a coding (which you guys thankfully didn't), I would definitely write down what was wrong with my code and thought process and try to make sure I don't make same mistakes again...

If you guys feel annoyed at repetitive newbie Q's, maybe you guys can redirect us newbs to a thread with similar Q's that has been solved or show us some hint that might help...

I'm gonna stop talking now...Anyways, thanks so much for everybody who helped me, and good day!

Hey skw4712, good follow up post. I'm glad you have taken on board what has been said.

No one hates here. Everyone was a newbie at some point

It's just that we get a lot of newbie type questions and Norm & dlorde are always on the front line answering them. The comments are all tongue-in-cheek.

You don't have to worry about asking questions here. Reading what you have wrote confirms that you are an ideal member to have.