写2个线程,其中一个线程打印1~52,另一个线程打印A~z,打印顺序应该是12A34B45C……5152Z

class LN
{
private int flag = 0;
public static char ch = 'A';
public static int n = 1;
public synchronized void printLetter()
{
try
{
if(flag == 0 || flag == 1)
{
wait();
}
else
{
//System.out.println("flag = " +     flag);
System.out.print(ch);
ch++;

flag = (flag + 1) % 3;

notifyAll();
}
}
catch(InterruptedException ex)
{
ex.printStackTrace();
}
}
public synchronized void printNumber()
{
try
{
if(flag == 2 )
{
wait();
}
else
{
//System.out.println("flag = " +     flag);
System.out.print(n);
n++;

flag = (flag + 1) % 3;

notifyAll();
}
}
catch(InterruptedException ex)
{
ex.printStackTrace();
}
}
}

class Letter extends Thread
{
LN ln;
Letter(LN ln)
{
this.ln = ln;
}
public void run()
{
for(int i = 0 ; i< 26; i++)
{
ln.printLetter();
}
}
}
class Number extends Thread
{
LN ln;
Number(LN ln)
{
this.ln = ln;
}
public void run()
{
for(int i = 0 ; i< 78; i++)
{
ln.printNumber();
}
}
}

class Practice1
{
public static void main(String[] args) {

LN ln = new LN();
new Letter(ln).start();
new Number(ln).start();
}
}

public class ThreadDemo {
// 测试
public static void main(String[] args) {
Object obj = new Object();
// 启动两个线程
Thread1 t1 = new Thread1(obj);
Thread2 t2 = new Thread2(obj);

t1.start();
t2.start();
}
}

class Thread1 extends Thread {
private Object obj;

public Thread1(Object obj) {
this.obj = obj;
}

public void run() {
// 加锁
synchronized (obj) {
// 打印1-52
for (int i = 1; i < 53; i++) {
System.out.print(i);
if (i % 2 == 0) {
// 不能忘了唤醒其它线程
obj.notifyAll();
try {
obj.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

}
}
}

class Thread2 extends Thread {
private Object obj;

public Thread2(Object obj) {
this.obj = obj;
}

public void run() {
synchronized (obj) {
// 打印A-Z
for (int i = 0; i < 26; i++) {
System.out.print((char) ('A' + i));
// 不能忘了唤醒其它线程
obj.notifyAll();
try {
obj.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}