任務是編寫一個程序來創建和啟動兩個線程 ThreadFibonacci 和 ThreadOutput。ThreadFiobnacci 應該計算斐波那契數并將結果放入其靜態公共變量中。ThreadOutput 應該輸出斐波那契數并且 ThreadOutput 必須是一個守護線程。你必須讓線程只寫出每個斐波那契數。我不知道如何完成任務的最后一部分。您只能使用 sleep、interrupt、volatile 和 join。這是我嘗試過的：import java.util.Scanner;public class Zadatak2{ public static void main(String[] args){ Scanner reader = new Scanner(System.in); System.out.println("Enter a number: "); int n = reader.nextInt(); Thread threadFibonaci = new Thread(new ThreadFibonaci(n)); Thread threadOutput = new ThreadOutput(); threadFibonaci.start(); threadOutput.start(); }}class ThreadFibonaci implements Runnable{ public static volatile long fn; private int n; public ThreadFibonaci(int n){ this.n = n; } public void run(){ long f0 = 0; fn = f0; try{ Thread.sleep(500); }catch(Exception e){ e.printStackTrace(); } long f1 = 1; fn = f1; try{ Thread.sleep(500); }catch(Exception e){ e.printStackTrace(); } for(int i=0; i<n; i++){ fn = f0 + f1; f0 = f1; f1 = fn; try{ Thread.sleep(500); }catch(Exception e){ e.printStackTrace(); } } }}class ThreadOutput extends Thread{ public ThreadOutput(){ setDaemon(true); } public void run(){ while(true){ System.out.println(ThreadFibonaci.fn); try{ Thread.sleep(500); }catch(Exception e){ e.printStackTrace(); } } }}
2 回答
米琪卡哇伊
TA貢獻1998條經驗 獲得超6個贊
您需要再使用一個volatile變量來存儲當前數字是否已打印的標志
class ThreadFibonaci implements Runnable{
public static volatile long fn;
public static volatile boolean printed = false;
private int n;
public ThreadFibonaci(int n){
this.n = n;
}
public void run(){
long f0 = 0;
fn = f0;
while (!printed) {
try{
Thread.sleep(500);
}catch(Exception e){
e.printStackTrace();
}
}
long f1 = 1;
fn = f1;
printed = false;
while (!printed) {
try{
Thread.sleep(500);
}catch(Exception e){
e.printStackTrace();
}
}
for(int i=0; i<n; i++){
fn = f0 + f1;
f0 = f1;
f1 = fn;
printed = false;
while (!printed) {
try{
Thread.sleep(500);
}catch(Exception e){
e.printStackTrace();
}
}
}
}
}
class ThreadOutput extends Thread{
public ThreadOutput(){
setDaemon(true);
}
public void run(){
while(true){
while (ThreadFibonaci.printed) {
try{
Thread.sleep(500);
}catch(Exception e){
e.printStackTrace();
}
}
System.out.println(ThreadFibonaci.fn);
ThreadFibonaci.printed = true;
}
}
}
Helenr
TA貢獻1780條經驗 獲得超4個贊
這使用單個volatile字段來保存值。當值為0新值時可以發布，當值為負時，它充當毒丸，停止打印線程。
class A {
static volatile long value = 0;
static void publish(long x) {
while (value > 0) ;
value = x;
}
static long next() {
while (value == 0) ;
long ret = value;
if (ret > 0) value = 0;
return ret;
}
public static void main(String[] args) {
System.out.println("Enter a number: ");
int n = new java.util.Scanner(System.in).nextInt();
new Thread(() -> {
long a = 1; publish(a);
long b = 1; publish(b);
for (int i = 2; i < n; i++) {
long c = a + b; publish(c);
a = b; b = c;
}
publish(-1); // poison pill
}).start();
new Thread(() -> {
for (; ; ) {
long value = next();
if (value < 0) break;
System.out.println(value);
}
}).start();
}
}
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