Thread: Exception Handling/Logic Problems

Hello, I would like the program to handle non-integer inputs essentially. Within Part 1, I would like it to ONLY take in values 1 and higher. Any value that is a non-int or 0 or <0 will lead to an if-statement checking for that, should any of those options be true. It will output, "Invalid Amount" and exit the program. For Part 2, if the value given is less than 0, higher than 50, or a non-integer, it is checked by an if-statement where should any of those be true, it will output, "Invalid Value." and once again, exit the program there. I hope this makes it more clear.

Edit:
I should state that the program works fine if you follow with what is saying, BUT by chance if the user inputs a character then a number. I would like the program to be able to handle those scenarios basically.

Part 1:

import java.text.DecimalFormat;
import java.util.Scanner;
 
public class testingCode {
 
	public static void main(String[] args) {
 
		//creating the scanner object
		Scanner  input = new Scanner(System.in);
		//Creating our DecimalFormat
		DecimalFormat df = new DecimalFormat("0.00");
 
		//Ask User for scores
		System.out.println("How many scores do you want to enter?");
		//boolean variable to handle non-integer values
		boolean hasInt = input.hasNextInt();
		int size = input.nextInt();
 
 
		//if-statement handling amount of size is less than 0 or a non-integer
		if(size <= 0 || !hasInt) {
			System.out.println("Invalid Amount.");
			System.exit(0);
		}//end if-statement

Part 2:

//Array
		int[] score = new int[size];
 
		int max = -1;
		int sum = 0;
		System.out.println("Please enter in " + size + " scores between 0-50");
		for(int index = 0; index < score.length; index++) {
 
			//take in the score and put it the array at the index
			score[index] = input.nextInt();
 
			//compare the value of the variable at that index to max
			if(score[index] > max)
				max = score[index];
 
			sum += score[index];
 
		}//end for

It was the order of that if-statement. I managed to get the program to work now finally how I wanted it. It handles those exceptions now. My only question now, if you don't mind answering, would be what could I do to make this more efficient/readable? If there are any improvements to be made. Anything is appreciated, and thank you for your time. The finished code is below:

 
import java.text.DecimalFormat;
import java.util.Scanner;
 
public class testingCode {
 
	public static void main(String[] args) {
 
		//creating the scanner object
		Scanner  input = new Scanner(System.in);
		//Creating our DecimalFormat
		DecimalFormat df = new DecimalFormat("0.00");
 
		//variable for 'size' of array
		int size = 0;
 
		//Ask User for scores
		System.out.println("How many scores do you want to enter?");
		//boolean variable to handle non-integer values
		boolean hasInt = input.hasNextInt();
		if(hasInt) {
			size = input.nextInt();
			if(size <= 0) {
				System.out.println("Invalid Amount.");
				System.exit(0);
			}//end if
		} else {
			System.out.println("Invalid Amount.");
			System.exit(0);
		}//end if-else
 
		//Array
		int[] score = new int[size];
 
		int max = -1;
		int sum = 0;
		System.out.println("Please enter in " + size + " scores between 0-50");
		//Exception Handling Below for Non-Integer values or values less than 0 or greater than 50
		hasInt = input.hasNextInt();
		if(hasInt) {
			for(int index = 0; index < score.length; index++) {
 
				//take in the score and put it the array at the index
				score[index] = input.nextInt();
				//Handling Integer Values outside of range
				if(score[index] < 0 || score[index] > 50) {
					System.out.println("Invalid Amount.");
					System.exit(0);
				}
 
				//compare the value of the variable at that index to max
				if(score[index] > max)
					max = score[index];
 
				sum += score[index];
			}//end if
		} else {
			System.out.println("Invalid Value.");
			System.exit(0);
		}//end if-else
 
		System.out.println("The max score is: " + max);
 
		double average = (double)sum/score.length;
 
		System.out.println("The average is: " + average);
 
		//standard deviation
		int total = 0;
		for(int index = 0; index < score.length; index++) {
			total += Math.pow(score[index] - average, 2);
		}//end for
 
		double standardDeviation = Math.sqrt(total * 1.0 / score.length);
 
		System.out.println("Standard Deviation: " + df.format(standardDeviation));
 
	}//end main
 
}//end class

Originally Posted by Norm

These comments are completely redundant. get rid of any similar ones that only repeat what the code is obviously doing
//creating the scanner object
Scanner input = new Scanner(System.in);
//Creating our DecimalFormat

No need for a variable, put the method in the if
boolean hasInt = input.hasNextInt();
if(hasInt) {

if( input.hasNextInt()) {

Thank you Norm. I'll keep that in mind moving forward. Have a great day.