多线程

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题目： 设计4个线程，其中两个每次对i++，剩下两个每次i--[/color]


public class 四线程加加渐渐 {

	int z=0;
	public static void main(String[] args) {
		四线程加加渐渐 zz = new 四线程加加渐渐();
		Inner1 in1 = zz.new Inner1();
		Inner2 in2 = zz.new Inner2();
        for(int i=0;i<2;i++){
        	Thread t = new Thread(in1);
        	t.start();
        	t = new Thread(in2);
        	t.start();
        }
	}
	
	class Inner1 implements Runnable {
		@Override
		public void run() {
			for(int i=0;i<100;i++){
				inc();
			}
		}
	}
		private void inc() {
			z++;
			System.out.println(Thread.currentThread().getName()+"-inner1:"+z);
		}
		
   class Inner2 implements Runnable {
	@Override
		public void run() {
			for(int i=0;i<100;i++){
				dec();
			}
		}
   }
		private void dec() {
			z--;
			System.out.println(Thread.currentThread().getName()+"-inner2:"+z);
		}
  
}
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public class 线程的加加减减 {

	 a a1 = new a();
	public static void main(String[] args) {
	  new 	线程的加加减减().call();
	}
   public   void call(){
	   for(int i=0;i<20;i++){
		   new Thread(new Runnable(){
			   public void run(){
				   //while(true){
					   a1.jia();
				   //}
			   }
		   }).start();
		   new Thread(
				   new Runnable(){
					   public void run(){
						  // while(true){
							   a1.jian();
						  // }
					   }
				   }).start();
	   }
   }
}

class a {
	private int i=0;
	public synchronized void jia(){
		i++;
		System.out.print(i);
	}
	
	public  synchronized void jian(){
		i--;
		System.out.print(i);
	}
}