I am trying to validate that the user only enters an integer. Is there another way to do this that will make the validation more simplified?
Scanner in = new Scanner(System.in);
System.out.print("Enter the amount of subjects that you need to get an average of: ");
int amount_of_subjects;
while (!in.hasNextInt())
{
// warning statement
System.out.println("Please Enter integer!");
in.nextLine();
}
amount_of_subjects = Integer.parseInt(in.nextLine());
It seems your solution is already quite simple. Here is a more minimalist version:
System.out.print("Please enter an integer: ");
while(!scan.hasNextInt()) scan.next();
int demoInt = scan.nextInt();
from https://stackoverflow.com/a/23839837/2746170
Though you would only be reducing lines of code while possibly also reducing readability.
Depending what you want to do with your program.
If you want to only take a valid Integer as input you can use the nextInt() function
Scanner scanner = new Scanner(System.in);
int number = scanner.nextInt();
If you want to check if the user is putting in a valid Integer to respond to that you can do something like:
public boolean isNumber(String string) {
try {
Integer.parseInt(string);
return true;
} catch (NumberFormatException e) {
return false;
}
}
Here is an easier approach which validates integer values 0 - max value inclusive and type checks the user input and finally displays result or error message. It's looped over and over until good data is received.
import java.util.Scanner;
import java.util.InputMismatchException;
class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int userVal = 0;
while(true){
try{
System.out.print("Enter a number: ");
userVal = scan.nextInt();
if ((userVal >= 0 && userVal <= Integer.MAX_VALUE)){
System.out.println(userVal);
break;
}
}
catch(InputMismatchException ex){
System.out.print("Invalid or out of range value ");
String s = scan.next();
}
}
}
}
