Producer Consumers Problem

#include<stdio.h>
int mutex=1,full=0,empty=3,x=0;
main()
{
int n;
void producer();
void consumer();
int wait(int);
int signal(int);
printf("\n 1.Producer \n 2.Consumer \n 3.Exit");
while(1){
printf("\n Enter 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;
}
}
}
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("\n Producer produces the item %d",x);
mutex=signal(mutex);
}
void consumer()
{
mutex=wait(mutex);
full=wait(full);empty=signal(empty);
printf("\n Consumer consumes item %d",x);
x--;
mutex=signal(mutex);
}