java基础1

第一章:java语言基础;

//第一个程序HelloWorld.java

package foxe;

public class HelloWorld {

/**
* @param args
*/
public static void main(String[] args) {
System.out.println("Hello,World!");
// TODO Auto-generated method stub

}

}

//第二个程序HelloWorld_Applet .java

package foxe;
import java.awt.Graphics;
import javax.swing.JApplet;
public class HelloWorld_Applet extends JApplet{

public void paint(Graphics g) {
g.drawString("Hello World!", 25, 25);


}

}

//for ,while,do-while         sum.java

package foxe;

public class Sum {

/**
* @param args
*/
public static void main(String[] args) {
int i=1,n=10,sum1=0,sum2=0,sum3=0;
//for circulation
for(i=1;i<=n;i++){
sum1=sum1+i;

}
System.out.println("for sum is :"+sum1);
i=1;
while(i<=n){
sum2=sum2+i;
i++;
}
System.out.println("while sum is :"+sum2);
i=1;
do{
sum3=sum3+i;
i++;
}while(i<=n);
System.out.println("do-while sum is :"+sum3);


}

}

第二章:类和对象

//参数传递ParameterTest .java

package foxe;

class Point{
int x=70;
int y=80;
}
class Circle{
int x=5,y=6;
Point point ;
void setXY(int x1,int y1){
x1=x;
y1=y;
}
void setPoint (Point ref){
ref.x=x;
ref.y=y;

}
}
public class ParameterTest {
//pass parameter test

/**
* @param args
*/

public static void main(String[] args) {
Circle p=new Circle();
int xValue=-1,yValue=-1;
System.out.println("value pass:");
p.setXY(xValue, yValue);
System.out.println("xValue="+xValue+",yValue="+yValue);

Point point=new Point();
p.setPoint(point);
System.out.println("address pass:");
System.out.print("point.x="+point.x+",point.y="+point.y);

}
}

//类变量和类方法与实例变量和实例方法;

 

package foxe;
class Member{
static int classVar;//类变量
int instanceVar;//实例变量
static void setClassVar(int i){
classVar=i;

//instanseVar=i;类方法不能访问实例变量

}
static int getClassVar(){//类方法
return classVar;

}
void setInstanceVar(int i){//实例方法
classVar=i;//实例方法可以访问类变量
instanceVar=i;

}
int getInstanceVar()
{
return instanceVar;

}

}

public class MemberTest {


public static void main(String[] args) {
Member m1=new Member();
Member m2=new Member();
m1.setClassVar(1);
m2.setClassVar(2);
System.out.println("m1.classVar="+m1.getClassVar()+",m2.classVar="+m2.getClassVar());

m1.setInstanceVar(11);
m2.setInstanceVar(22);
System.out.println("m1.InstanceVar="+m1.getInstanceVar()+",m2.InstanceVar="+m2.getInstanceVar());

Member.classVar=3;
System.out.println("m1.ClassVar="+m1.getClassVar()+",m2.ClassVar="+m2.getClassVar());
System.out.println("ClassVar="+Member.getClassVar());

}

}

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java基础1

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