第三章第二十三题（几何：点是否在矩形内？）(Geometry: point in a rectangle?)

• **3.23（几何：点是否在矩形内？）编写程序。提示用户输入点（x，y），然后检测该点是否在以原点（0，0）为中心、宽为10、高为5的矩形中。例如：（2，2）在矩形内，而（6，4）在矩形外。
  这里有两个运行示例：
  Enter a point with two coordinates:2 2
  Point (2.0, 2.0) is in the rectangle
  Enter a point with two coordinates:6 4
  Point (6.0, 4.0) is not in the rectangle

  **3.23(Geometry: point in a rectangle?)Write a program that prompts the user to enter a point (x, y) and checks whether the point is within the rectangle centred at (1, 1) with width 10 and height 5. For example, (2, 2) is inside the rectangle and (6, 4) is outside the rectangle.
  Here are two sample runs.
  Enter a point with two coordinates:2 2
  Point (2.0, 2.0) is in the rectangle
  Enter a point with two coordinates:6 4
  Point (6.0, 4.0) is not in the rectangle

• 参考代码：

package chapter03;import java.util.Scanner;public class Code_23 {public static void main(String[] args) {double pointX,pointY;System.out.print("Enter a point with two coordinates:");Scanner input = new Scanner(System.in);pointX = input.nextDouble();pointY = input.nextDouble();// Check if the point is in the rectangleif((pointX >= -5 && pointX <= 5) && (pointY >= -2.5 && pointY <= 2.5))System.out.println("Point " + "(" + pointX + "," + pointY + ")"+ " is in the rectangle");elseSystem.out.println("Point " + "(" + pointX + "," + pointY + ")"+ " is not in the rectangle");input.close();}
}

• 结果显示：

Enter a point with two coordinates:2 2
Point (2.0,2.0) is in the rectangleProcess finished with exit code 0