JuniorTheoryCommon

What does the program print?

JAVA

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        int[] a = {1, 2};
        int[] b = {1, 2};
        System.out.println((a == b) + " " + Arrays.equals(a, b));
    }
}

false true

Expecting true true: == on arrays compares references, and two literals {1, 2} create two separate arrays.
Expecting Arrays.equals to need the very same array: it compares the length and each element in order, so equal contents give true.

What does Arrays.equals return for {1, 2} and {2, 1}?
After int[] c = a;, what does a == c print?

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JuniorTheoryCommon

What does the program print?

JAVA

import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        int[] a = {1, 2};
        int[] b = {1, 2};
        System.out.println((a == b) + " " + Arrays.equals(a, b));
    }
}

false true

Expecting true true: == on arrays compares references, and two literals {1, 2} create two separate arrays.
Expecting Arrays.equals to need the very same array: it compares the length and each element in order, so equal contents give true.

What does Arrays.equals return for {1, 2} and {2, 1}?
After int[] c = a;, what does a == c print?

Back to questions Open topic in roadmap →Answer it yourself — Quiz