Part 95 to 96 Deadlock in a multithreaded program，deadlock
Part 95 Deadlock in a multithreaded program
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class Program
{
static void Main(string[] args)
{
Console.WriteLine("main start");
Account a1 = new Account(001,10000);
Account a2 = new Account(002,20000);
AccountManager m1 = new AccountManager(a1,a2,5000);
Thread t1 = new Thread(m1.Transfer);
t1.Name = "t1";
AccountManager m2 = new AccountManager(a2, a1, 3000);
Thread t2 = new Thread(m2.Transfer);
t2.Name = "t2";
t1.Start();
t2.Start();
t1.Join();
t2.Join();
Console.WriteLine("main end");
}
}
class Account
{
public int ID { get; set; }
public double Balance { get; set; }
public Account(int id, double balance)
{
this.ID = id;
this.Balance = balance;
}
public void WithDraw(double amount)
{
Balance -= amount;
}
public void Deposit(double amount)
{
Balance += amount;
}
}
class AccountManager
{
public Account FromAccount { get; set; }
public Account ToAccount { get; set; }
public double AmountToTransfer { get; set; }
public AccountManager(Account from,Account to,double amountToTransfer)
{
this.FromAccount = from;
this.ToAccount = to;
this.AmountToTransfer = amountToTransfer;
}
public void Transfer()
{
Console.WriteLine(Thread.CurrentThread.Name+"try to acquire lock on"+FromAccount.ID.ToString());
lock (FromAccount)
{
Console.WriteLine(Thread.CurrentThread.Name+" acquired lock on "+FromAccount.ID.ToString());
Console.WriteLine(Thread.CurrentThread.Name+" suspended for 1 second");
Thread.Sleep(1000);
Console.WriteLine(Thread.CurrentThread.Name+"back in action and try to acquire lock on" +ToAccount.ID.ToString());
lock (ToAccount)
{
Console.WriteLine("this code will not execute");
FromAccount.WithDraw(AmountToTransfer);
ToAccount.Deposit(AmountToTransfer);
}
}
}
}
View Code
Part 96 How to resolve a deadlock in a multithreaded program
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static void Main(string[] args)
{
Console.WriteLine("main start");
Account a1 = new Account(101,10000);
Account a2 = new Account(102,20000);
AccountManager m1 = new AccountManager(a1,a2,5000);
Thread t1 = new Thread(m1.Transfer);
t1.Name = "t1";
AccountManager m2 = new AccountManager(a2, a1, 3000);
Thread t2 = new Thread(m2.Transfer);
t2.Name = "t2";
t1.Start();
t2.Start();
t1.Join();
t2.Join();
Console.WriteLine("main end");
}
}
class Account
{
public int ID { get; set; }
public double Balance { get; set; }
public Account(int id, double balance)
{
this.ID = id;
this.Balance = balance;
}
public void WithDraw(double amount)
{
Balance -= amount;
}
public void Deposit(double amount)
{
Balance += amount;
}
}
class AccountManager
{
public Account FromAccount { get; set; }
public Account ToAccount { get; set; }
public double AmountToTransfer { get; set; }
public AccountManager(Account from,Account to,double amountToTransfer)
{
this.FromAccount = from;
this.ToAccount = to;
this.AmountToTransfer = amountToTransfer;
}
public void Transfer()
{
object _lock1, _lock2;
if(FromAccount.ID<ToAccount.ID)
{
_lock1 = FromAccount;
_lock2 = ToAccount;
}
else
{
_lock1 = ToAccount;
_lock2 = FromAccount;
}
Console.WriteLine(Thread.CurrentThread.Name+"try to acquire lock on "+((Account)_lock1).ID.ToString());
lock (_lock1)
{
Console.WriteLine(Thread.CurrentThread.Name + " acquired lock on " + ((Account)_lock1).ID.ToString());
Console.WriteLine(Thread.CurrentThread.Name+" suspended for 1 second");
Thread.Sleep(1000);
Console.WriteLine(Thread.CurrentThread.Name + "back in action and try to acquire lock on " + ((Account)_lock2).ID.ToString());
lock (_lock2)
{
Console.WriteLine(Thread.CurrentThread.Name + " acquired lock on " + ((Account)_lock2).ID.ToString());
FromAccount.WithDraw(AmountToTransfer);
ToAccount.Deposit(AmountToTransfer);
Console.WriteLine(Thread.CurrentThread.Name+" Transferd "+AmountToTransfer.ToString()+" from "+FromAccount.ID.ToString()+" to "+ToAccount.ID.ToString());
}
}
}
View Code
