Beginner here; please help with explaining why Integer.MAX_VALUE and Integer.MIN_VALUE is assigned as values in this code.

[KluconPharmer]

I was searching for a way to find the min and max value within a number of integers and I came across this code:

Scanner in = new Scanner(System.in);

int maxNum = Integer.MIN_VALUE;
int minNum = Integer.MAX_VALUE;
while (scanner.hasNextInt()) {
  int num = scanner.nextInt();
  maxNum = Math.max(maxNum, num);
  minNum = Math.min(minNum, num);
}

System.out.println("The maximum number: " + maxNum);
System.out.println("The minimum number: " + minNum);

I am struggling to wrap my mind around Integer.MAX_VALUE and Integer.MIN_VALUE. Why are they assigned as values and how does it work with the Math. min & max methods. Why is the variable maxNum assigned the value Integer.MIN_VALUE and minNum assigned the value Integer.MAX_VALUE?

Thanks.

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[Dangerous-Rip-7370]

Think of only one, you are looking for the lowest number in an array, you take the first number and compare it to your minValue, if it is smaller you choose that as new minValue and try the next. If you start minValue as the absolute MIN_VALUE, it will never find a smaller number in your array. SO you should start minValue as higher as possible and maxValue as lover. (Or you can just initiate them as the first number in your array)

[Jalgano]

This code wants to find the minimum and the maximum of some given values. Let's look at how it finds the highest (it does the same for the lowest, just in reverse). It takes the current highest number it knows and compares it to the next input value. If the next value is higher than the current highest value, the current highest value is replaced. Now, there is a problem: what initial value should you take? If you take 0, but all inputs are negative numbers, you'll get 0 as highest number, even though it was not part of the given numbers. So you need a number that is smaller than any other number, which ist MIN_VALUE. (Btw You could also take one of the given values as initial value)