Producer Consumer Problem Implementation

This section discusses an implementation of the classic producer-consumer problem using the pthreads library.
The source code will be examined section by section.
Reference the source code link in the instructor's notes if any confusion arises during the explanation.

Global Variables Defined:
- A global scope where key shared variables are initialized and defined.

Buffer Characteristics:
- Size of the shared buffer is defined as:
- $buffer ext{ size} = 3$
This buffer can hold three elements concurrently.

Important Shared Variables:
- num: Represents the number of elements currently in the buffer.
- Initial Value: $num = 0$
- add: Index for the next position to add an element in the buffer.
- Initial Value: $add = 0$
- rem: Index for the next position to remove an element from the buffer.
- Initial Value: $rem = 0$

Following steps illustrate how shared variables change as elements are added or removed from the buffer.

Adding First Element:
- Update: $num = 1$ , $add = 1$ , $rem = 0$
- Indicates that one element has been added; the next addition should occur in buffer position indexed by add (1).
Adding Second Element:
- Update: $num = 2$ , $add = 2$ , $rem = 0$
- Two elements are now in the buffer, next addition should go to index 2.

Removing First Element:
- Update: $num = 1$ , $add = 2$ , $rem = 1$
- One element has been removed; still need to add at index 2; the next valid entry to be removed is at index 1.

Mutex Usage:
- A mutex is utilized in the implementation to manage concurrent access to shared resources.
- A mutex initializer statement automatically initializes the mutex, performing the function of attribute initialization.
Condition Variables:
- Two condition variables are defined:
1. c_cons: Used by consumers.
  - Consumers will wait on this condition variable to consume items from the buffer.
2. c_prod: Used by producers.
  - Producers will wait on this condition variable to produce items into the buffer.