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I’ve been trying to get a 10×10 2D array filled diagonally as in the image below for a couple hours now, but after checking every possible way to use rows and collums I still can’t seem to identify my misunderstanding of the code.
What im supposed to get:
this is how far ive gotten, i dont understand what im doing wrong
int n = 1;
for (int i=0; i<=9; i++) {
for (int j=9-i ; j>=7-i; j--) {
if (j>=0)
m[i][j] = n++;
}
}
>Solution :
You first need to loop your rows, and knowing that it’s a diagonal loop, the starting point at each step will be the (i, i) tuple. Starting from there, an inner loop loops up to 2 further elements and updates the values at the given place if they are inside bounds. Whenever we set a value to a given element, we decrement currentIndex, so we will not have to worry about its value.
import java.util.*;
import java.lang.*;
import java.io.*;
// The main method must be in a class named "Main".
class Main {
public static void main(String[] args) {
int currentIndex = 27;
int[][] array = new int[10][10];
for (int i = 0; i < array.length; i++) {
for (int j = i; j <= i + 2 && (j < array[i].length); j++) {
array[i][j] = currentIndex--;
}
}
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array.length; j++) {
System.out.print((array[j][i] > 9 ? "" : " ") + array[j][i] + " ");
}
System.out.println();
}
}
}