阅前声明: http://blog.csdn.net/heimaoxiaozi/archive/2007/01/19/1487884.aspx
**(From Dan Forhan) Write a java program that will find all the possible “vampire numbers.” A vampire number is defined as a four digit numbers in which the two numbers multiplied are in the product, for example, 15 x 93 = 1395. The program should produce no duplicates, and be less than 50-60 lines of code.
// Solution by Dan Forhan import java.applet.*; import java.awt.*; public class Vampire extends Applet { private int num1, num2, product; private int[] startDigit = new int[4]; private int[] productDigit = new int[4]; private int count = 0; private int vampCount = 0; private int x, y; public void paint(Graphics g) { g.drawString("Vampire Numbers", 10, 20); g.drawLine(10, 22, 150, 22); // Positioning for output to applet: int column = 10, row = 35; for(num1 = 10; num1 <= 99; num1++) for(num2 = 10; num2 <= 99; num2++) { product = num1 * num2; startDigit[0] = num1 / 10; startDigit[1] = num1 % 10; startDigit[2] = num2 / 10; startDigit[3] = num2 % 10; productDigit[0] = product / 1000; productDigit[1] = (product % 1000) / 100; productDigit[2] = product % 1000 % 100/10; productDigit[3] = product % 1000 % 100; count = 0; for(x = 0; x < 4; x++) for(y = 0; y < 4; y++) { if (productDigit[x] == startDigit[y]){ count++; productDigit[x] = -1; startDigit[y] = -2; if (count == 4) { vampCount++; int a = (int)Math.random() * 100; int b = (int)Math.random() * 100; int c = (int)Math.random() * 100; if (vampCount < 10) { g.drawString("Vampire number " + vampCount + " is " + num1 + " * " + num2 + " = "+ product, column, row); row += 20; } else { g.drawString("Vampire number " + vampCount + " is " + num1 + " * " + num2 + " = "+ product, column, row); row += 20; } } } } } } }