Producer Consumer

#include<stdio.h>

void produce(int data);
void consume();
void wait();
void signal();
void psignal();
void pwait(int data);
void cwait();
void csignal();
void display();
int buffer[10];
int front,rear,size;

struct semaphore
{
 int mutex;
}s;

struct list
{
 int num;
 struct list *next;
}*hp1,*hp2,*cur,*p,*cp,*q;

 void main()
 {
  int ch,k;

  s.mutex=1;
  front=0;
  rear=0;
  hp1=hp2=NULL;
  printf("\nPRODUCER CONSUMER PROBLEM");
  printf("\nEnter the size of buffer (<10) : ");
  scanf("%d",&size);
  size++;

  do
  {
   printf("\n1. Produce an item\n2. Consume an item\n3. exit");
   printf("\n\nEnter your choice : ");
   scanf("%d",&ch);

   switch(ch)
   {
    case 1: wait();
        printf("\nEnter data to be produced : ");
        scanf("%d",&k);
        produce(k);
        csignal();

        printf("\n\n");

        display();
        signal();
        break;
    case 2: wait();
        consume();
        psignal();
        printf("\n\n");
        display();
        signal();
        break;
    case 3: exit(0);
   }
  }while(ch<3);

}

void produce(int data)
{
 if((rear+1)%(size)==front)
 {
  pwait(data);
  printf("\nProducer is Waiting");
 }
 else
 {
  rear=(rear+1)%size;
  buffer[rear]=data;

  printf("\nITEM PRODUCED IS : %d",data);
 }
}

void consume()
{
 int no;
 if (front==rear)
 {
  cwait();
  printf("\nConsumer is waiting");
 }
 else
 {
  front=(front+1)%size;
  no=buffer[front];
  buffer[front]=0;
  printf("\nITEM CONSUMED IS : %d",no);
 }
}

void pwait(int data)
{
 cur=(struct list*)malloc(sizeof(struct list));
 cur->next=NULL;
 cur->num=data;
 if(hp1==NULL)
 {
  hp1=cur;
 }
 else
 {
  q=hp1;
  while(q->next!=NULL)
  q=q->next;
  q->next=cur;
 }
}

void cwait()
{
 cp=(struct list*)malloc(sizeof(struct list));
 cp->next=NULL;
 cp->num=1;
 if(hp2==NULL)
 {
  hp2=cur;
 }
 else
 {
  q=hp2;
  while(q->next!=NULL)
   q=q->next;
  q->next=cp;
 }
}

void csignal()
{
 struct list *c;
 if(hp2==NULL)
  return;
 else
 {
  consume();
  c=hp2;
  hp2=hp2->next;
  free(c);
 }
}

void psignal()
{
 struct list *r;
 if(hp1==NULL)
  return;
 else
 {
  produce(hp1->num);
  r=hp1;
  hp1=hp1->next;
  free(r);
 }
}

void wait()
{
 while(s.mutex==0);
 if(s.mutex==1)
  s.mutex=0;
 }

void signal()
{
 s.mutex=s.mutex+1;
}

void display()
{
 int i,count;
 if(front==-1)
  i=0;
 else
  i=front;
 printf("\n\n");
 for(count=0;count<size;)
 {
  printf("\t%d",buffer[i]);
  count++;
  i=(i+1)%size;
 }
}
/*
        /************OUTPUT***********

PRODUCER CONSUMER PROBLEM
Enter the size of buffer (<10) : 2

1. Produce an item
2. Consume an item
3. exit

Enter your choice : 1

Enter data to be produced : 1

ITEM PRODUCED IS : 1




               1       0
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 1

Enter data to be produced : 2

ITEM PRODUCED IS : 2



               1       2
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 1

Enter data to be produced : 3

Producer is Waiting



               1       2
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 2


ITEM CONSUMED IS : 1
ITEM PRODUCED IS : 3



              2       3
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 2

ITEM CONSUMED IS : 2



               3       0
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 2

ITEM CONSUMED IS : 3



               0       0
1. Produce an item
2. Consume an item
3. exit

Enter your choice : 2

Consumer is waiting



              0       0
1. Produce an item
2. Consume an item
3. exit

Enter your choice :


         */