Thread: My first functioning Try Catch program

I have chosen a do-while loop mechanism for my first try catch Java program, but it's kind of a mess:

package sam;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Scanner;
 
public class Test {
 
	public static void main(String[] args){
		System.out.println("Lets play with some try catch statements.");
		Scanner input = new Scanner(System.in);
		int x=1, num1=1, num2=1;
 
		do{
			try{				
				System.out.println("Enter the first (dividend) int: ");
				num1 = input.nextInt();
				int parsedNum1 = Integer.parseInt(num1);
				System.out.println("Enter the second (divisor) int: ");
				num2 = input.nextInt();	
				int parsedNum2 = Integer.parseInt(num2);
 
				int quotient = num1 / num2;//dividend / divisor
				System.out.println("Our quotient is: " + quotient);
 
				x = 2;//when the user enters proper input, change x, so that the while condition below can terminate our do while loop.				
			}
			catch(NumberFormatException e){
				//check if num1 is an integer
				//check if num2 is an integer
				//statement to catch a NumberFormatException?
 
				System.out.println("Error. Invalid dividend or divisor. Please try again.");
				continue;
 
			}
		}while(x==1);		
 
	}//end of main
}//end of class Test

Lines 17 and 20 keep throwing the same error, "The method parseInt(String) in the type Integer is not applicable for the arguments (int)".

I don't understand how the "e" parameter works in line 27's catch statement. Does it have to be "e" for a special reason? Would it still work if I used "fred" for the parameter instead?

I'm unsure how to proceed making exception handlers. Am I just supposed to use a bunch of if statements? Do I need to use the continue statement in a do-while loop?

Originally Posted by SamJava_the_Hut

I have chosen a do-while loop mechanism for my first try catch Java program, but it's kind of a mess:

package sam;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Scanner;
 
public class Test {
 
	public static void main(String[] args){
		System.out.println("Lets play with some try catch statements.");
		Scanner input = new Scanner(System.in);
		int x=1, num1=1, num2=1;
 
		do{
			try{				
				System.out.println("Enter the first (dividend) int: ");
				num1 = input.nextInt();
				int parsedNum1 = Integer.parseInt(num1);
				System.out.println("Enter the second (divisor) int: ");
				num2 = input.nextInt();	
				int parsedNum2 = Integer.parseInt(num2);
 
				int quotient = num1 / num2;//dividend / divisor
				System.out.println("Our quotient is: " + quotient);
 
				x = 2;//when the user enters proper input, change x, so that the while condition below can terminate our do while loop.				
			}
			catch(NumberFormatException e){
				//check if num1 is an integer
				//check if num2 is an integer
				//statement to catch a NumberFormatException?
 
				System.out.println("Error. Invalid dividend or divisor. Please try again.");
				continue;
 
			}
		}while(x==1);		
 
	}//end of main
}//end of class Test

Lines 17 and 20 keep throwing the same error, "The method parseInt(String) in the type Integer is not applicable for the arguments (int)".

I don't understand how the "e" parameter works in line 27's catch statement. Does it have to be "e" for a special reason? Would it still work if I used "fred" for the parameter instead?

I'm unsure how to proceed making exception handlers. Am I just supposed to use a bunch of if statements? Do I need to use the continue statement in a do-while loop?

why you using NextInt? and then Tryin to Parse Int to int value as Norm said .

you should change your Varies to Strings , int x;
then try to play with it

and you can add e.getMessage() to catch block . in my opinion it seems better .

This is a joke. Why is NumberFormatException not doing anything:

public class Test {
 
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		int userInput = 12;
		boolean stayInLoop = true;
 
		do{
			try{				
				System.out.println("Enter an integer between 0 and 10.");
				userInput = input.nextInt();
				//int parsedUserInput = Integer.parseInt(userInput);				
 
				stayInLoop = false;//break;				
			}
			catch(NumberFormatException e){
				if(userInput > 0 && userInput < 10){
					System.out.println("Your integer is not between 0 and 10. Try again!"); 
				}
				else{
					e.getMessage();
				}
				//statement to catch a datatype input mismatch by user?								
				continue;				
			}
		}while(stayInLoop==true);
		System.out.println("You're out of the loop after entering " + userInput);
 
	}//end of main
}//end of class Test

Not only does my if statement not work:

Enter an integer between 0 and 10.
13
You're out of the loop after entering 13


But my program simply crashes instead of continuing the do while loop:
Enter an integer between 0 and 10.
12.3
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:875)
at java.util.Scanner.next(Scanner.java:1496)
at java.util.Scanner.nextInt(Scanner.java:2128)
at java.util.Scanner.nextInt(Scanner.java:2087)
at sam.Test.main(Test.java:16)

And here I thought that try catch mechanisms were supposed to correct the user, not crash the program.

Originally Posted by jim829

That is not the exception you are catching.

I still don't understand. Is Try Catch supposed to catch errors, or correct them? What can Try Catch do to correct errors that if statements cannot?