Thread: exception handling

Hi, before anyone trashes my question, I have not been taught this yet so forgive my ignorance. I would like to correctly handle the exception for user input of 1-4 when someone inputs a letter instead. This is my code so far. It all works except the handling part( I know its not right, but do not know how to do it right, yet.) Any help in understanding how to do this would be greatly appreciated.

 
 
import java.util.Scanner;
import java.io.Console;
 
class WeatherProgram{
 
	public static void main(String[]args){
		double fahrenheit = 0;
		double celsius = 0;
		double chill = 0;
		double reply;
		String reply2 = "y";
		Console c = System.console();
		Scanner scan = new Scanner(System.in);
 
		while(reply2.equals("y")){
 
			try {
				System.out.println("Welcome to Weather Conversion. Please choose one of the following numbers: "+"\n");
				System.out.println("1. Fahrenheit to Celsius");
				System.out.println("2. Celsius to Fahrenheit");
				System.out.println("3. Windchill");
				System.out.println("4. Quit"+"\n");
				reply = scan.nextDouble();
			}
 
			catch (java.util.InputMismatchException){
			}
 
			if (reply != (1-4)){
				System.out.println("I'm sorry, that is not a chioce. Please choose 1-4: "+"\n");
				System.out.println("Welcome to Weather Conversion. Please choose one of the following numbers: "+"\n");
				System.out.println("1. Fahrenheit to Celsius");
				System.out.println("2. Celsius to Fahrenheit");
				System.out.println("3. Windchill");
				System.out.println("4. Quit"+"\n");
				reply = scan.nextDouble();
			}
 
			if (reply == 1){
				fToC(fahrenheit);
			}
 
			if (reply == 2){
				cToF(celsius);
			}
 
			if (reply == 3){
				tToWC(chill);
			}
			reply2 = c.readLine("Do you wish to continue Weather Conversion, (y/n)?: ");
		}
		System.out.println("Thank you");
	}
 
	static double fToC(double fahrenheit){
		double celsius;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input fahrenheit temperature: ");
		fahrenheit = scan.nextDouble();
		celsius = ((fahrenheit-32)*5/9);
 
		if (celsius<1){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius. Temperature is below freezing!");
		}
		if (celsius>32){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius. It is hot!");
		}
		if((celsius>1) && (celsius<32)){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius.");
		}
		return celsius;
	}
 
	static double cToF(double celsius){
		double fahrenheit;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input celsius temperature: ");
		celsius = scan.nextDouble();
		fahrenheit = ((celsius*9/5)+32);
 
		if (fahrenheit<33){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit. Temperature is below freezing!");
		}
		if (fahrenheit>90){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit. It is hot!");
		}
		if((fahrenheit>33) && (fahrenheit<90)){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit.");
		}
		return fahrenheit;
	}
 
	static double tToWC(double chill){
		double temperature;
		double windSpeed;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input temperature in degrees fahrenheit: ");
		temperature = scan.nextDouble();
		System.out.println("Please input wind speed in MPH: ");
		windSpeed = scan.nextDouble();
		chill = (35.74 + (0.6215*temperature) - (35.75*Math.pow(windSpeed,0.16)) + (.4275*temperature*Math.pow(windSpeed,0.16)));
 
		if (chill<-30){
			System.out.println("Windchill = " + chill + " Degrees Fahrenheit. Dangerous Windchill!");
		}
		else{
			System.out.println("Windchill = " + chill + " Degrees Fahrenheit");
		}
		return chill;
	}
}

Ya, I'm sorry, rewrote the code. Here is the new code. Would still like to error handle the exception possibility of input being a letter and not a number with a try/catch.Please help with try/catch(haven't been taught yet).

 
 
import java.util.Scanner;
import java.io.Console;
 
class WeatherProgram0{
 
	public static void main(String[]args){
		double reply1 = 0;
		mainProgram(reply1);
	}
 
	static double mainProgram(double reply1){
		double fahrenheit = 0;
		double celsius = 0;
		double chill = 0;
		String reply2 = "y";
		Console c = System.console();
		Scanner scan = new Scanner(System.in);
 
		while(reply2.equals("y")){
			System.out.println("Welcome to Weather Conversion. Please choose one of the following numbers: "+"\n");
			System.out.println("1. Fahrenheit to Celsius");
			System.out.println("2. Celsius to Fahrenheit");
			System.out.println("3. Windchill"+"\n");
			reply1 = scan.nextDouble();
 
			if (reply1 == 1){
				fToC(fahrenheit);
			}
			if (reply1 == 2){
				cToF(celsius);
			}
			if (reply1 == 3){
				tToWC(chill);
			}
		System.out.println("");
		reply2 = c.readLine("Would you like to continue Weather Program, (y/n)?");
		}
		System.out.println("Thank you");
		return(reply1);
	}
 
	static double fToC(double fahrenheit){
		double celsius;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input fahrenheit temperature: ");
		fahrenheit = scan.nextDouble();
		celsius = ((fahrenheit-32)*5/9);
 
		if (celsius<1){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius. Temperature is below freezing!");
		}
		if (celsius>32){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius. It is hot!");
		}
		if((celsius>1) && (celsius<32)){
			System.out.println(fahrenheit + " Fahrenheit = " + celsius + " Celsius.");
		}
		return celsius;
	}
 
	static double cToF(double celsius){
		double fahrenheit;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input celsius temperature: ");
		celsius = scan.nextDouble();
		fahrenheit = ((celsius*9/5)+32);
 
		if (fahrenheit<33){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit. Temperature is below freezing!");
		}
		if (fahrenheit>90){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit. It is hot!");
		}
		if((fahrenheit>33) && (fahrenheit<90)){
			System.out.println(celsius + " Celsius = " + fahrenheit + " Fahrenheit.");
		}
		return fahrenheit;
	}
 
	static double tToWC(double chill){
		double temperature;
		double windSpeed;
		Scanner scan = new Scanner(System.in);
		System.out.println("Please input temperature in degrees fahrenheit: ");
		temperature = scan.nextDouble();
		System.out.println("Please input wind speed in MPH: ");
		windSpeed = scan.nextDouble();
		chill = (35.74 + (0.6215*temperature) - (35.75*Math.pow(windSpeed,0.16)) + (.4275*temperature*Math.pow(windSpeed,0.16)));
 
		if (chill<-30){
			System.out.println("Windchill = " + chill + " Degrees Fahrenheit. Dangerous Windchill!");
		}
		else{
			System.out.println("Windchill = " + chill + " Degrees Fahrenheit");
		}
		return chill;
	}
}