Java) Temperature Converter

First flowchart

Second Flowchart

It looks very complicated and lacks visual attraction, but I tried and learned at least!

Third Flowchart after Feedback

Help: Omar Shalaby

 

After realizing "Think twice, Code once" is important, these are my first flow charts. I thought three times and coded twice, but it helped me to understand how my algorithms have to be.

 

First Code

import java.util.Scanner;

//Temperature Converter Far -> Cel / Cel -> Far
public class TempConverter {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		String num1;
		int tem, press;
		double num2, num3;
		// boolean tof = false;
		Scanner sc = new Scanner(System.in);

		System.out.println("Press 1 to convert Fahrenheit to Celsius, Press 2 to convert from Celsius to Fahrenheit. ");
		press = sc.nextInt();
		// while (true) {
		try {

			while (true) {
				if (press == 1) {
					System.out.println("Enter Fahrenheit.");
					sc.nextLine();// The "Enter" key after inputting the number is considered as one input.
					// By inserting this line, you can avoid the output of "Not a number" right
					// away.
					num1 = sc.nextLine();

					// while (true) {
					try {
						num2 = Double.parseDouble(num1);
						// To check if int is inserted or not.

						// formula: (32°F − 32) × 5/9 = 0°C
						num3 = ((((num2 - 32.0) * 5.0) / 9.0));
						System.out.printf("%.2f", num3);
						System.out.println();
						return;

					} catch (NumberFormatException n) {
						System.out.println("Not a number. Please enter again.");
						sc.nextLine();
					}
				} else if (press == 2) {
					System.out.println("Enter Celsius.");
					sc.nextLine();
					num1 = sc.nextLine();

					try {
						num2 = Double.parseDouble(num1);
						// To check if int is inserted or not.

						// (0°C × 9/5) + 32 = 32°F
						num3 = (((num2 * 9) / 5) + 32);
						System.out.printf("%.2f", num3);
						System.out.println();

					} catch (NumberFormatException nn) {
						System.out.println("Not a number.");

					}
				}
			}
		} catch (Exception e) {
			System.out.println("Invalid Access. Please enter again.");

		}

		// }

	}
}

Second Code(Final)

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class TempConverter2 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		try {
			System.out.println("From Fahrenheit to Celsius press 1, vice versa, press 2.");
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			String inputString = br.readLine();
			int num = Integer.parseInt(inputString);

			if (num == 1) {
				farToCel();
			} else if (num == 2) {
				celToFar();
			} else {
				System.out.println("Not a valid access.");
			} 

		} catch (Exception eo) {
			System.out.println("Not a number.");
		}
	}

	public static void farToCel() {
		while (true) {
			try {
				BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
				System.out.println("Please enter number.");
				String inputString = br.readLine();
				double far = Double.parseDouble(inputString);
				double result1 = ((((far - 32.0) * 5.0) / 9.0));

				System.out.printf("%.2f", result1);
				System.out.println();
				System.out.println("To repeat press anything, to finish, press F or f.");
				String inputString2 = br.readLine();
				if (inputString2.equals("F") || inputString2.equals("f")) {
					System.out.println("Finish the program.");
					break; // to go back to the main menu
				} else {
					continue;
				}
			} catch (Exception e) {
				System.out.println("Not a number.");
			}

		}
	}

	public static void celToFar() {
		while (true) {
			try {
				BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
				System.out.println("Please enter number.");
				String inputString = br.readLine();
				double cel = Double.parseDouble(inputString);
				double result2 = (((cel * 9) / 5) + 32);

				System.out.printf("%.2f", result2);
				System.out.println();
				System.out.println("To go repeat press anything, to finish, press F or f.");
				String inputString3 = br.readLine();
				if (inputString3.equals("F") || inputString3.equals("f")) {
					System.out.println("Finish the program.");
					break;
				} else {
					continue;
				}
			} catch (Exception ei) {
				System.out.println("Not a number.");
			}

		}
	}
}