面向对象总结——2017.08.02

方法的参数传递机制：只能是值传递

package Collection;

public class ZhiCd {
	//此处如果不加静态static
	//Exception in thread "main" java.lang.Error: Unresolved compilation problem:
  //	Cannot make a static reference to the non-static method swap(int, int) from the type ZhiCd

	public static void swap(int a,int b)
	{
		int temp;
		temp = a;
		a=b;
		b=temp;
		System.out.println("swap:"+"a:"+a+"  "+"b:"+b);

	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int a=9;
		int b=6;
		swap(a, b);
		System.out.println("a:"+a+"  "+"b:"+b);

	}

}

package Collection;

 class DataWrap
 {
	 int a;
	 int b;
 }
public class ReferenceTransferTest {
	/**
	 * @param dw
	 */
	public static void swap(DataWrap dw)
	{
		int temp;
		temp=dw.a;
		dw.a=dw.b;
		dw.b=temp;
		System.out.println("DataWrap方法"+dw.a+"  "+dw.b);
	}

	public static void main(String[] args) {
		DataWrap dw=new DataWrap();
//		DataWrap dw=null;
		dw.a=6;
		dw.b=9;
		swap(dw);
		System.out.println("DataWrap方法后"+dw.a+" "+dw.b);

	}

}

递归方法：

例子：

f(0)=1,f(1)=4,f(n+2)=2*f(n+1)+f(n)

package Collection;
public class Recursive {
	public static int fn(int n)
	{
		if(n==0)
		{
			return 1;
		}
		else if(n==1)
		{
			return 4;
		}
		else {
			return 2*fn(n-1)+fn(n-2);
		}
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    System.out.println(fn(10));
    //10497
	}

}