黑马程序员技术交流社区

标题: 面试点招题----多线程之十个线程求和之四种不同解法 [打印本页]

作者: wolfking0608 时间: 2016-10-8 21:13
标题: 面试点招题----多线程之十个线程求和之四种不同解法
解法一:
*  10个线程
* */
//创建10个线程，线程一从1加到10，线程2从11加到20....最后把十个线程的结果相加。
/**
* 思路：
* 1.创建一个类，实现runnable接口,
* 2.定义2个成员变量，线程的初始值，线程的总量，
* 3.定义一个设置线程初始值的方法和获取线程总量的方法
* 4.重写run方法，每一个线程除了初始值不一样外，相加的类容都一样，获取单个线程的量。
* 5.将每个线程的量都相加。
* 6.在,main方法中创建共享数据对象
* 7.创建10个线程的的数组
* 8.遍历数组，获取每一个线程，给其赋初始值，
* 9.开启线程，并让线程插队
*
*/
public class 多线程_10个线程_100的和 {

  public static void main(String[] args) throws InterruptedException {
   //创建共享资源数据
   MyThread4 my = new MyThread4();
   //创建10个线程数组
   Thread[] arr=new Thread[10];
   //遍历该数组
   for (int i = 0; i < arr.length; i++) {
      //创建线程
      Thread t=new Thread(my,"线程"+i);
      //设置该线程的初始值
      my.setStr(10*i+1);
      //开启线程
      t.start();
      //线程等待
      t.join();
   }
   System.out.println(MyThread4.getSum());
  }
}
class MyThread4 implements Runnable{
  private int str;//线程的初始值
  private static int sum;//所有线程数量和
  //设置线程赋初始值方法
  public void setStr(int str){
   this.str=str;
  }
  //获取所有线程的数量的方法
  public static int getSum(){
   return sum;
  }
  //重写run方法
  public void run() {
   //设置初始值
   int num=0;
   //获取一个线程的量
   for (int i = 0; i < 10; i++) {
      num+=str+i;
   }
   //调用添加方法
   add(num);

  }
  //把每一个线程的量相加
  private void add(int num) {
   sum+=num;

  }

}

解法二:
public class 线程100 {
private static int num=100;
static  ArrayList<Integer> list = new ArrayList<>();
static int s1=0;
static int s2=0;
static int s3=0;
static int s4=0;
static int s5=0;
static int s6=0;
static int s7=0;
static int s8=0;
static int s9=0;
static int s10=0;

public static void main(String[] args) throws InterruptedException {
   final Test01 t = new Test01();
   System.out.println("--------------1----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=90){
   break;
   }
   for (int i = 1; i <=10; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s1=count/10;

   }
   }.start();
   System.out.println("--------------2----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=80){
   break;
   }
   for (int i = 11; i <=20; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s2=count/10;
   }
   }.start();
   System.out.println("--------------3----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=70){
   break;
   }
   for (int i = 21; i <=30; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s3=count/10;
   }
   }.start();
   System.out.println("--------------4----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=60){
   break;
   }
   for (int i = 31; i <=40; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s4=count/10;
   }
   }.start();
   System.out.println("--------------5----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=50){
   break;
   }
   for (int i = 41; i <=50; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s5=count/10;
   }
   }.start();
   System.out.println("--------------6----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=40){
   break;
   }
   for (int i = 51; i <=60; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s6=count/10;
   }
   }.start();
   System.out.println("-------------7-----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=30){
   break;
   }
   for (int i = 61; i <=70; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s7=count/10;
   }
   }.start();
   System.out.println("--------------8----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=20){
   break;
   }
   for (int i = 71; i <=80; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s8=count/10;
   }
   }.start();
   System.out.println("---------------9---------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=10){
   break;
   }
   for (int i = 81; i <=90; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s9=count/10;
   }
   }.start();
   System.out.println("--------------10----------");
   new Thread(){
public void run(){
   int count=0;
   while(true){
   synchronized(t){
   if(num<=0){
   break;
   }
   for (int i = 91; i <=100; i++) {
   count+=i;
}
   num--;
   }
   }
   System.out.println(count/10);
   list.add(count/10);
   s10=count/10;
   return;
   }
   }.start();
   int c=0;
   //目的是让前面的线程执行完了,之后才让这个线程睡觉,睡的时间不够长的话,结果会出现问题
   Thread.currentThread().sleep(10);
   for (int i = 0; i < list.size(); i++) {
   c+=list.get(i);
}
   System.out.println("List集合中打印的结果:"+c);
   Thread.currentThread().sleep(10);//目的是让前面的线程执行完了,,睡的时间不够长的话,结果会出现问题
//System.out.println(list.size());
// System.out.println("总数为:"+c/10);
   int k =s1+s2+s3+s4+s5+s6+s7+s8+s9+s10;
   System.out.println("总数为:"+k);
}
}
解法三:
   public class 线程求和 extends Thread{

static int num = 0;
int number;
public 线程求和(int n) {
number = n;
}
public static int getNum() {
return num;
}
@Override
public void run() {
int count = 0;
for (int i = 0; i < 10; i++) {
count += number + i;
}
num = count;
System.out.println(number + "+" + (number + 1) + "+...+" + (number + 9) + "=" + count);
}

public static void main(String[] args) throws InterruptedException {
int a = 0;
for (int i = 0; i < 10; i++) {
int k = i * 10 + 1;
线程求和 tt = new 线程求和(k);
tt.start();
tt.sleep(10);
a = a + tt.getNum();

}
System.out.println(a);

}
}

解法四:
public class Demo09_10个线程的和 {
@SuppressWarnings("static-access")
public static void main(String[] args) throws InterruptedException {
for (int i = 0; i < 10; i++) {
int k = i * 10 + 1;
ThreadTest tt = new ThreadTest(k);
tt.start();
}
Thread.currentThread().sleep(100);
System.out.println("-----"+ThreadTest.num);
}

}

class ThreadTest extends Thread {
int number;
static int num;

public ThreadTest(int n) {
number = n;
}

public void run() {
int count = 0;
for (int i = 0; i < 10; i++) {
count += number + i;
}
System.out.println(number + "+" + (number + 1) + "+...+" + (number + 9)
+ "=" + count);
num+=count;

}
}

作者: 马文丽 时间: 2016-10-8 21:51
以后多多分享{:2_31:}

作者: Quasimodo2 时间: 2016-10-8 22:34
哦哦哦哦

欢迎光临黑马程序员技术交流社区 (http://bbs.itheima.com/)

黑马程序员IT技术论坛 X3.2