Java code for Pascal's Triangle.

PascalsTriangle.java

public class PascalsTriangle {
    private int[][] triangle;
    
    /* Creates a new PascalsTriangle representation with n rows. */
    public PascalsTriangle(int n) {
        triangle = new int[n][n];
        
        // The first column is all 1's.
        for (int i = 0; i < n; i++) {
            triangle[i][0] = 1;
        }
        
        // We fill in the rest by summing the two elements above.
        for (int i = 1; i < n; i++) {
            for (int j = 1; j < n; j++) {
                triangle[i][j] = triangle[i-1][j] + triangle[i-1][j-1];
            }
        }
    }

    public void print() {
        for (int i = 0; i < triangle.length; i++) {
            for (int j = 0; j < triangle[i].length; j++) {
                System.out.print(triangle[i][j] + " ");
            }
            System.out.println();
        }
    }
    
    public static void main(String[] args) {
        PascalsTriangle pascal = new PascalsTriangle(5);
        pascal.print();
    }
}