Synchronization Producer Consumer Problem

source Code:

#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("\nBuffer is full!!");
break;
case 2: if((mutex==1)&&(full!=0))
consumer();
else
printf("\nBuffer 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);
}