类继承，定义了一个点类point，然后线条类line继承了point类，正方形类Suare继承line类
正方形四个角坐标关系如图
1 /**
2 *
3 java继承实例。
4
5
6 定义了一个点类point，然后线条类line继承了point类，正方形类square继承line类。
7
8 */
9
10 //点类
11 class PointDemo
12 {
13 private int x;
14 private int y;
15 private static int pCount=0;
16
17 //默认初始化坐标点（0,0），坐标点数计数+1
18 PointDemo(){
19 this.x=0;
20 this.y=0;
21 pCount++;
22 }
23
24 //带有x,y坐标参数构造函数，坐标点数计数+1
25 PointDemo(int x, int y){
26 this.x=x;
27 this.y=y;
28 pCount++;
29 }
30
31 //设置坐标x,y值
32 public void setPoint(int x,int y){
33 this.x=x;
34 this.y=y;
35 }
36
37 //返回获取X,Y坐标值
38 public int getX(){return x;}
39 public int getY(){return y;}
40
41 //返回程序累积坐标计数
42 public static int getPCount(){return pCount;}
43
44 }
45
46 //行类继承点类
47 class LineDemo extends PointDemo
48 {
49 private PointDemo po1;
50 private PointDemo po2;
51 private float range;
52 private static int lCount=0;
53
54 //返回程序累积线数计数
55 public static int getLCount(){return lCount;}
56
57 //默认空参构造函数，默认坐标(0,0),(4,3),初始化两坐标之间的长度，线数计数+1
58 LineDemo(){
59 po1=new PointDemo();
60 po2=new PointDemo(4,3);
61 setRange();
62 lCount++;
63 }
64
65 //两坐标参数构造函数，初始化两坐标和坐标之间的长度，线数计数+1
66 LineDemo(PointDemo po1,PointDemo po2){
67 this.po1=po1;
68 this.po2=po2;
69 setRange();
70 lCount++;
71 }
72
73 //返回获取两点坐标值
74 public PointDemo getPo1(){return po1;}
75 public PointDemo getPo2(){return po2;}
76
77 //设置两点之间的长度
78 public void setRange(){
79 range=(float)Math.sqrt(Math.pow(Math.abs(po2.getX()-po1.getX()),2)+Math.pow(Math.abs(po2.getY()-po1.getY()),2));;
80 }
81 public float getRange(){return range;}
82
83 //输出两点坐标及两点之间的距离
84 public void out(){
85 System.out.println("___________________________");
86 System.out.println("("+po1.getX()+","+po1.getY()+")");
87 System.out.println("("+po2.getX()+","+po2.getY()+")");
88 System.out.println("range="+range);
89 System.out.println("===========================");
90 }
91 }
92
93 //正方型类
94 /*
95 (X1,Y1),(X2,Y2),(X3,Y3),(X4,Y4)
96 A = X2-X1, B = Y2-Y1;
97 X3 = X1+(A-B) = X1+(X2-X1-Y2+Y1) = X2-Y2+Y1;
98 Y3 = Y1+A+B = Y1+X2-X1+Y2-Y1 = X2-X1+Y2;
99 X4 = -(X2-(A-B)) = -(X2+Y2-Y1-X2+X1) = Y1-X1-Y2;
100 Y4 = Y2+(A-B) = Y2+X2-X1-Y2+Y1 = X2-X1+Y1;
101
102 */
103 class Square extends LineDemo
104 {
105 private LineDemo[] line = new LineDemo[6];
106 private PointDemo[] point = new PointDemo[4];
107 private static int sCount=0;
108
109 //返回累积正方形个数计数
110 public static int getSCount(){return sCount;}
111
112 //空参构造函数，默认初始化正方形四个角坐标及边长和周长的长度，正方形个数计数+1
113 Square(){
114 super();
115 setSquarePoint();
116 setSquareLine();
117 sCount++;
118 }
119
120 //两坐标点参数构造函数，初始化正方形四个角坐标及边长和周长的长度，正方形个数计数+1
121 Square(PointDemo po1,PointDemo po2){
122 super(po1,po2);
123 point[0]=po1;
124 point[1]=po2;
125 setSquarePoint();
126 setSquareLine();
127 sCount++;
128 }
129
130 //一条边长做参数的构造函数，初始化正方形四个角坐标及边长和周长的长度，正方形个数计数+1
131 Square(LineDemo line){
132 super(line.getPo1(),line.getPo2());
133 point[0]=line.getPo1();
134 point[1]=line.getPo2();
135 setSquarePoint();
136 setSquareLine();
137 sCount++;
138 }
139
140 //设置正方形四个角坐标
141 private void setSquarePoint(){
142 int x1=point[0].getX();
143 int y1=point[0].getY();
144 int x2=point[1].getX();
145 int y2=point[1].getY();
146 point[2] = new PointDemo(x2-y2+y1,x2-x1+y2);
147 point[3] = new PointDemo(y1-x1-y2,x2-x1+y1);
148 }
149
150 //设置正方形所有边长和对角线坐标及长度
151 private void setSquareLine(){
152 for (int i=0,k=0;i<point.length ;i++ )
153 {
154 for (int j=i+1;j<point.length ;j++,k++ )
155 {
156 line[k] =new LineDemo(point[i],point[j]);
157 }
158 }
159
160 }
161
162 //输出所有边长和对角线坐标及长度
163 public void outAllLine(){
164 for (LineDemo li : line)
165 {
166 li.out();
167 }
168 }
169
170 //输出正方形四个角坐标
171 public void outPoint(){
172 for (int i=0;i<point.length ;i++ )
173 {
174 System.out.println("point["+i+"] = ("+point[i].getX()+","+point[i].getY()+")");
175 }
176 }
177 }
178
179 class ExtendsDemo
180 {
181 public static void main(String[] args)
182 {
183 //测试点
184 PointDemo[] pArr = new PointDemo[10];
185 for (int i=0,j=10;i<pArr.length ;i++,j-- )
186 {
187 pArr[i]=new PointDemo(i,j);
188 }
189 for (PointDemo po: pArr )
190 {
191 System.out.println("("+po.getX()+","+po.getY()+")");
192 }
193 System.out.println("pointCount="+PointDemo.getPCount()+"\n");
194
195 //测试线
196 LineDemo line = new LineDemo();
197 line.out();
198 System.out.println("lineCount="+LineDemo.getLCount()+"\n");
199 LineDemo line1 = new LineDemo(pArr[0],pArr[9]);
200 line1.out();
201 System.out.println("lineCount="+LineDemo.getLCount()+"\n");
202 System.out.println("pointCount="+LineDemo.getPCount()+"\n");
203
204 //测试正方形
205 Square su = new Square(line1);
206 System.out.println("显示所有坐标");
207 su.outPoint(); //显示所有坐标
208 System.out.println("显示所有边坐标及长度");
209 su.outAllLine(); //显示所有边坐标及长度
210 System.out.println("SquareCount="+Square.getSCount()+"\n");
211 }
212 }
时间： 2024-10-06 15:32:06