2013-08-03 261 views
-1

嗨,我正在学习Java,发现一个相当整洁的解决方案, 但我对第二个for循环中的特定代码行感兴趣。 我不知道是谁问,因为我在学校的Java我没有,所以我问这里, 但无论如何:Java嵌套for循环第一循环递增第二循环?

for (int i = 0; i < BRICKS_IN_BASE + (-h); i++) 

这是否意味着“重复i此次数” '加'到'h减1'?更具体什么是(-h)?这是一个预增量吗?为什么在括号中?

它再次用于声明变量x

import acm.graphics.*; 
import acm.program.*; 
import java.awt.*; 

public class Pyramid extends GraphicsProgram { 

    /** Width of each brick in pixels */ 
    private static final int BRICK_WIDTH = 30; 

    /** Width of each brick in pixels */ 
    private static final int BRICK_HEIGHT = 12; 

    /** Number of bricks in the base of the pyramid */ 
    private static final int BRICKS_IN_BASE = 15; 

    public void run() { 
     for (int h = 0; h < BRICKS_IN_BASE; h++) 
     { 
      for (int i = 0; i < BRICKS_IN_BASE + (-h); i++) 
      { 
       int k = i * BRICK_WIDTH; 
       int m = h * BRICK_HEIGHT; 
       int x = ((getWidth() - ((BRICKS_IN_BASE + (-h)) * BRICK_WIDTH))/2) + k; 
       int y = getHeight() - ((BRICK_HEIGHT + 1) + m); 
       GRect brick = new GRect (x, y, BRICK_WIDTH, BRICK_HEIGHT); 
       add(brick); 
      } 
     }    
    } 
} 
+1

也许输入'INT I = 1; System.out.println(1 +(-i));'进入你的电脑,看看会发生什么? –

回答

0
for (int i = 0; i < BRICKS_IN_BASE + (-h); i++) 

是真(第(-h)是简单地-1 * H)

for (int i = 0; i < (BRICKS_IN_BASE - h); i++) 

由于operator precedence