CSC-111 Two Dimensional Array Example

PascalTriangle.java

// (x+1)^0    1                             1
// (x+1)^1    1   1                         x + 1
// (x+1)^2    1   2   1                     x^2 + 2x + 1
// (x+1)^3    1   3   3   1                 x^3 + 3x^2 + 3x + 1 
// (x+1)^4    1   4   6   4   1             x^4 + 4x^3 + 6x^2 + 4x + 1
// (x+1)^5    1   5  10  10   5  1          x^5 + 5x^4 + 10x^3 + 10x^2 = 5x + 1
// (x+1)^6    1   6  15  20  15  6  1       ...
// ...


public class PascalTriangle {
	public static void main(String args[]) {
		int pt[][] = new int[10][10];
		generateTriangle(pt);
		printTriangle(pt);
		printXplus1Expansions(pt);
	}
	
	private static void generateTriangle(int x[][]) {
		for (int row = 0; row < x.length; row++) {
			x[row][0] = 1;
			x[row][row] = 1;
			for (int col = 1; col < row; col++) 
				x[row][col] = x[row-1][col-1] + x[row-1][col];				
		}
	}
	
	private static void printTriangle(int x[][]) {
		for (int row = 0; row < x.length; row++) {
			for (int col = 0; col <= row; col++) 
				System.out.printf("%6d", x[row][col]);
			System.out.println();
		}
	}
	
	private static void printXplus1Expansions(final int x[][]) {
		if (x == null || x.length == 0)
			return;
		for (int row = 0; row < x.length; row++) {
			if (row == 0) {
				System.out.printf("1");
				System.out.println();				
			}
			else if (row == 1) {
				System.out.printf("x + 1");
				System.out.println();				
			}
			else {
				System.out.printf("x^%d", row);
				for (int col = 1; col < row; col++) {
					if (col == row - 1) {
						System.out.printf(" + %dx", x[row][col]);
					}
					else {
						System.out.printf(" + %dx^%d", x[row][col], row - col);			
					}
				}
				System.out.printf(" + %d", 1);
				System.out.println();
			}
		}
	}
}

PascalTriangle2.java

public class PascalTriangle2 {
	public static void main(String args[]) {
		int pt[][] = generateTriangle();
		printTriangle(pt);
	}
	
	//   i -> array
	//   0 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   1 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   2 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   3 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   4 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   5 -> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
	//   ...
	private static int[][] generateTriangle() {
		int x[][] = new int[10][10];
		for (int row = 0; row < x.length; row++) {
			x[row][0] = 1;
			x[row][row] = 1;
			for (int col = 1; col < row; col++) 
				x[row][col] = x[row-1][col-1] + x[row-1][col];				
		}
		return x;
	}
	
	private static void printTriangle(int x[][]) {
		for (int row = 0; row < x.length; row++) {
			for (int col = 0; col <= row; col++) 
				System.out.printf("%6d", x[row][col]);
			System.out.println();
		}
	}
}

PascalTriangle3.java

public class PascalTriangle3 {
	public static void main(String args[]) {
		var pt = initStructure(10);
		generateTriangle(pt);
		printTriangle(pt);
	}
	
	//   i -> array
	//   0 -> [0]
	//   1 -> [0, 0]
	//   2 -> [0, 0, 0]
	//   3 -> [0, 0, 0, 0]
	//   4 -> [0, 0, 0, 0, 0]
	//   5 -> [0, 0, 0, 0, 0, 0]
	//   ...
	
	private static int[][] initStructure(final int size) {
		var x = new int[size][];
		for (int i = 0; i < size; i++)
			x[i] = new int[i+1];
		return x;
	}
	
	private static void generateTriangle(final int x[][]) {
		for (int row = 0; row < x.length; row++) {
			x[row][0] = 1;
			x[row][row] = 1;
			for (int col = 1; col < row; col++) 
				x[row][col] = x[row-1][col-1] + x[row-1][col];				
		}
	}
	
	private static void printTriangle(final int x[][]) {
		for (int row = 0; row < x.length; row++) {
			for (int col = 0; col <= row; col++) 
				System.out.printf("%6d", x[row][col]);
			System.out.println();
		}
	}
}

TwoDArrayExample.java

public class TwoDArrayExample {

	private static int[][] initMatrix(int numRows, int numCols) {
		int x[][] = new int[numRows][numCols];
		for (int i = 0; i < x.length; i++)
			for (int j = 0; j < x[i].length; j++)
				x[i][j] = (int) (100 * Math.random()) + 1;
		return x;
	}

	private static void printMatrix(int[][] x) {
		for (int i = 0; i < x.length; i++) {
			for (int j = 0; j < x[i].length; j++)
				System.out.printf("%5d", x[i][j]);
			System.out.println();
		}
	}
	
	private static int biggest(int numbs[][]) {
		int largest = numbs[0][0];
		for (int i = 0; i < numbs.length; i++)
			for (int j = 0; j < numbs[i].length; j++)
				if (numbs[i][j] > largest)
					largest = numbs[i][j];
		return largest;
	}

	public static void main(String args[]) {
		int x[][] = initMatrix(10, 8);
		printMatrix(x);
		System.out.printf("Biggest Number in Array = %d\n", biggest(x));
	}

}