多线程协作打印 (完美世界2017秋招真题)

【多线程协作打印 (完美世界2017秋招真题)】建立m个线程,每个线程只能打印一种字符,要求线程同时运行,交替打印n次字符。
比如: n=3 m=2打印字符为A和B。要求线程1打印3次A,线程2打印3次B,在屏幕输出ABABAB
注意: 需要检查输入有效性,遇到错误输入时,请打印error并安全退出。

import java.util.Scanner; public class Main { public static int count = 0; public static void main(String args[]) { Scanner sc = new Scanner(System.in); int n; String s; while (sc.hasNextInt()) { n = sc.nextInt(); s = sc.next(); if (!(n + "").matches("\\+?[1-9][0-9]*") || s == null || s.length() <= 0) { System.out.println("error"); return; } else { Object ob = new Object(); for (int i = 0; i < s.length(); i++) { new MyThread(s.charAt(i), i, s.length(), ob).start(); } } } } static class MyThread extends Thread { char c; int index; int length; Object ob; public MyThread(char c, int index, int length, Object ob) { this.c = c; this.index = index; this.length = length; this.ob = ob; }@Override public void run() { print(); }public void print() { synchronized (ob) { for (int i = 0; i < length; i++) { while (count % length != index) { try { ob.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } System.out.print(c); count++; ob.notifyAll(); } }} } }







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