CODEWITHSUNDEEP
javalogicternary-operator
Bob
Bob

Reputation: 417

Comparing three numbers with the Java logical-ternary operator?

I'm trying to create a method that returns the smallest value of three values (all bytes). Here is what I have:

public static byte findSmallestOfThree(byte n1, byte n2, byte n3) {
    return n1 > n2 ? n2 : n1 > n3 ? n3 : n1;
}

Now, the issue I'm having is that it doesn't always work.

Here are some inputs, and the outputs:

9, 10, 11 -> 9

10, 9, 11 -> 9

10, 11, 9 -> 9

11, 10, 9 -> 10

As you can see, when I entered 11, 10, 9 (in that order), I got 10 as the result (even though it should have been 9).

What is wrong with my logic? I think I've messed something up with the ternary operators, but I'm not sure what it is...

Upvotes: 2

Views: 10845

Answers (5)

Prabhat
Prabhat

Reputation: 51

Code to find the greatest of three numbers using ternary operator: 

public class FindGraterUsingTernaryOperator {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter the 3 Numbers to Check the Grater:::");
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int result = c > (a > b ? a : b) ? c : ((a > b) ? a : b);
    System.out.println("Grater Between 3 Numbers Is::" + result);
  }
}

Upvotes: 0

vBelt
vBelt

Reputation: 45

To get the max value out of three numbers, one line method:

int min = (a < b && a < c) ? a : ((b < a && b < c) ? b : c);

Upvotes: 0

Bohemian
Bohemian

Reputation: 425208

This works for me (I made them int for easier testing):

public static int findSmallestOfThree(int n1, int n2, int n3) {
    return n1 < n2 ? n1 < n3 ? n1 : n3 : n2 < n3 ? n2 : n3;
}

If you care more about readability than speed:

public static int findSmallestOfThree(int n1, int n2, int n3) {
    return Math.min(n1, Math.min(n2, n3));
}

Here's some simple test code:

public static void main(String[] args) {
    System.out.println(findSmallestOfThree(9, 10, 11));
    System.out.println(findSmallestOfThree(10, 9, 11));
    System.out.println(findSmallestOfThree(10, 11, 9));
    System.out.println(findSmallestOfThree(11, 10, 9));
    System.out.println(findSmallestOfThree(9, 11, 10));
    System.out.println(findSmallestOfThree(11, 9, 10));
}

Upvotes: 1

Edson Tirelli
Edson Tirelli

Reputation: 3901

byte min = n1 < n2 ? n1 : n2;
return min < n3 ? min : n3;

Upvotes: 0

Jim Kiley
Jim Kiley

Reputation: 3652

It's not a mistake with the ternary operators; it's a mistake with the comparisons. Your code says: if n1 > n2, return n2. So in the fourth example, 11 > 10, so it returns 10.

You have to compare n1 to both n2 and n3 to know that it's the greatest or lowest. You really want something like 

return (n1 <= n2) && (n1 <= n3) ? n1 : (n2 <= n3)? n2 : n3

(note: not actually tested)

Upvotes: 3

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