1
class fushu
{
int a;//实部
int b;//虚部
public fushu(int x,int y)
{
this.a=x;
this.b=y;
}
public fushu add(fushu add1)
{
int x=add1.a+this.a;
int y=add1.b+this.b;
return new fushu(x,y);
}
public fushu plus(fushu sub1)
{
int x=this.a-sub1.a;
int y=this.b-sub1.b;
return new fushu(x,y);
}
public String toString() {
String rt = "";
if (b > 0)
rt = "(" + a + "+" + b + "i" + ")";
if (b == 0)
rt = "(" +a + ")";
if (b < 0)
rt = "(" + a + b + "i" + ")";
return rt;
}
public static void main(String [] args)
{
fushu fushu1=new fushu(3,4);
fushu fushu2=new fushu(2,-13);
fushu result=fushu1.add(fushu2);
System.out.println(result);
//System.out.println("result="+result.a+"+"+result.b+"i");
}
}
2. //InterfaceTest.java
//主类InterfaceTest
public class InterfaceTest{
public static void main(String args[]){
MyLine line=new MyLine( 15);
MyCircle circle=new MyCircle(10);
MyRect rect = new MyRect(10,20);
Shape shapes[]=new Shape[3];
shapes[0]=line;
shapes[1]=circle;
shapes[2]=rect;
String output=
line.toString() + "\n"
+circle.toString() + "\n" + rect.toString();
for (int i = 0; i < shapes.length; i++){
output += "\n\n" +
" " + shapes[i].toString() +
"\nArea = " +
shapes[i].length();
}
System.out.println();
System.out.println(output);
}
}
//定义接口Shape
interface Shape{
//计算长度
public abstract double length();
}
//定义类Point
class MyLine
implements Shape{
private int length;
public MyLine(int length) {
this.length=length;
}
public String toString(){
return "this is MyLine" ;
}
public double length(){
return length;
}
}
class MyCircle
implements Shape{
protected double radius;
public MyCircle(double circleRadius ){
this.radius=circleRadius;
}
public double length(){
return 2*Math.PI * radius;
}
public String toString(){
return "this is a Circle";
}
}
class MyRect
implements Shape{
protected int height;
protected int width;
public MyRect(int height,int width){
this.height=height;
this.width=width;
}
public double length(){
return 2 *(height+width);
}
public String toString(){
return "this is a rectangle";
}
}