How to implement a read-write lock in C++ ?

Question

Write a thread safe data structure such that there could be only one writer at a time but there could be n readers reading the data. You can consider that incrementing or decrementing a variable is an atomic operation. If more than one threads try to write simultaneously then just select one randomly and let others wait.

Answer 1

Class ReadWriteLock
{
private int Read;
private int Write;
private static Object _S= new Object();
public void ReadWriteLock()
{
Write=0;
Read=0;
}
public void GetReadLock()
{
while(Write);
Interlocked.Increment(ref Read);
}

public void ReleaseReadLock()
{

 Interlocked.Decrement(ref Read);

}

public void GetWriteLock()
{
while(Read);
if(Read==0)
{
lock(_S)
{
if(Read==0)
{
Interlocked.Increment(ref Write);
}
}
}
}
}
public void ReleaseWriteLock()
{
Interlocked.Decrement(ref Write);
}