Producer Consumer Problem in C

Here you will learn about producer consumer problem in C.

Producer consumer problem is also known as bounded buffer problem. In this problem we have two processes, producer and consumer, who share a fixed size buffer. Producer work is to produce data or items and put in buffer. Consumer work is to remove data from buffer and consume it. We have to make sure that producer do not produce data when buffer is full and consumer do not remove data when buffer is empty.

Also Read: Banker’s Algorithm in C

The producer should go to sleep when buffer is full. Next time when consumer removes data it notifies the producer and producer starts producing data again. The consumer should go to sleep when buffer is empty. Next time when producer add data it notifies the consumer and consumer starts consuming data. This solution can be achieved using semaphores.

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Producer Consumer Problem in C

Below is the program to implement this problem.

#include<stdio.h>
#include<stdlib.h>

int mutex=1,full=0,empty=3,x=0;

int main()
{
	int n;
	void producer();
	void consumer();
	int wait(int);
	int signal(int);
	printf("\n1.Producer\n2.Consumer\n3.Exit");
	while(1)
	{
		printf("\nEnter your choice:");
		scanf("%d",&n);
		switch(n)
		{
			case 1:	if((mutex==1)&&(empty!=0))
						producer();
					else
						printf("Buffer is full!!");
					break;
			case 2:	if((mutex==1)&&(full!=0))
						consumer();
					else
						printf("Buffer is empty!!");
					break;
			case 3:
					exit(0);
					break;
		}
	}
	
	return 0;
}

int wait(int s)
{
	return (--s);
}

int signal(int s)
{
	return(++s);
}

void producer()
{
	mutex=wait(mutex);
	full=signal(full);
	empty=wait(empty);
	x++;
	printf("\nProducer produces the item %d",x);
	mutex=signal(mutex);
}

void consumer()
{
	mutex=wait(mutex);
	full=wait(full);
	empty=signal(empty);
	printf("\nConsumer consumes item %d",x);
	x--;
	mutex=signal(mutex);
}

Output

1.Producer
2.Consumer
3.Exit
Enter your choice:1

Producer produces the item 1
Enter your choice:2

Consumer consumes item 1
Enter your choice:2
Buffer is empty!!
Enter your choice:1

Producer produces the item 1
Enter your choice:1

Producer produces the item 2
Enter your choice:1

Producer produces the item 3
Enter your choice:1
Buffer is full!!
Enter your choice:3