bitwsie and + - swap - explain the output

[Kalpesh Soni]

package test;

public class SwapEm {

	public static void main(String[] args) {
		System.out.println(Integer.MAX_VALUE);
		swapPlus(Integer.MAX_VALUE-1,2);
		swapXOR(Integer.MAX_VALUE-1,2);
	}

	private static void swapXOR(int i, int j) {
		i = i | j;
		j = i ^ j;
		i = i^ j;
		System.out.println(i);
		System.out.println(j);
		System.out.println("..");
	}

	private static void swapPlus(int i, int j) {
		i = i+j;
		j = i-j;
		i = i-j;
		System.out.println(i);
		System.out.println(j);
		System.out.println("..");
	}

}

[Roel De Nijs]

Please UseCodeTags next time you post a code snippet

[Roel De Nijs]

Which of the outputs you don't understand?

Let's start with swapPlus-method and add some more debugging info:

    private static void swapPlus(int i, int j) {
        System.out.printf("i[%d] j[%d]\n", i, j);
        i = i + j;
        System.out.printf("i[%d] j[%d]\n", i, j);
        j = i - j;
        System.out.printf("i[%d] j[%d]\n", i, j);
        i = i - j;
        System.out.printf("i[%d] j[%d]\n", i, j);
    }

The output is as follows:
i[2147483646] j[2]
i[-2147483648] j[2]
i[-2147483648] j[2147483646]
i[2] j[2147483646]

[Kalpesh Soni]

I was reading some article and someone said A | B, A ^ B, A ^ B swaps variables without tempraroay 3rd var

but it doesnt, you have to use 3 XORs

[Roel De Nijs]

Kalpesh Soni wrote:I was reading some article and someone said A | B, A ^ B, A ^ B swaps variables without tempraroay 3rd var

Indeed variables aren't swapped, but maybe that's a typo.