Java increment declaration in for loop

Question

public class F2E12 {

    public static final int DIM = 5;

    public static void main(String[] args) {
        printMatrix(DIM);

    }

    public static void printMatrix(int n) {
        int i = 0;
        int j = 0;
        for(;i<=n;i++) {
            for(;j<=n;j++) {
                System.out.print(j + " ");
            }
            System.out.print("\n");

        }
    }
}

I want to print a matrix which increments the first number of each row by one. The above code should produce:

0 1 2 3 4 5
1 0 1 2 3 4
2 1 0 1 2 3
3 2 1 0 3 4
4 3 2 1 0 1
5 4 3 2 1 0

Instead it prints. "0 1 2 3 4 5"

Mad Penguin · Accepted Answer · 2018-09-16 12:18:35Z

7

public static void printMatrix(int n) {
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= n; j++) {
            System.out.print(Math.abs(j - i) + " ");
        }
        System.out.print("\n");
    }
}

answered Sep 16, 2018 at 12:18

Mad Penguin

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Comments

Elliott Frisch · Accepted Answer · 2018-09-16 12:13:09Z

4

Your current code doesn't work because j hits n on the first iteration of i. You could move j into the loop like

// int j = 0;
for (; i <= n; i++) {
    int j = 0;
    for (; j <= n; j++) {

to fix that.

answered Sep 16, 2018 at 12:13

Elliott Frisch

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