Thread: help in Circular Queue implementation

hello there this program i wrote it to do circular queue
but i have many error can you help me ?

Code:

#include<stdio.h>
#include<conio.h>
#define max 9
struct cQueue
{
int front,rear;
int items[max];
} ;
int isempty(struct cQueue *q)
{
if(q->front==q->rear)
return 1;
else
return 0;
}
void create(struct cQueue *q)
{
q->front=q->rear=0;
}
void display(struct cQueue *q)
{
int i;
if(isempty(*q))
printf("\n circular Queue is underflow ");
else
{
if(q->front==0)
q->front++;
for(int i=q->front;i!=q->rear;i=(i+1)%max)
{
printf("%d ",q->items[i]);
}
}
int isfull(struct cQueue *q)
{
if(((q->rear++)%max)==q->front)
return 1;
else
return 0;
}
void insert(struct cQueue *q,int d)
{
if(isfull(*q)==1)
printf("Circular Queue Overflow\n");
else
{
q->items[q->rear]=d;
q->rear=(q->rear++)%max;
printf("data inserted\n");
}
int remove(struct cQueue *q)
{
int del;
if(isempty(*q)==1)
printf("Circular Queue Underflow\n");
else
{
del=q->items[q->front];
q->front=(q->front++)%max;
}
return del;
}
void main()
{
struct cQueue q;
int x;
clrscr();
do{
printf("1-Create New Circular Queue\n2-add New element to Circular Queue\n");
printf("3-Remove element from Circular Queue\n4-Display all element of Circular Queue\n5-Exit");
printf("Enter Your Chocie:");
scanf("%d",&x);
switch(x)
{
case 1:
create(&q,x);
break;
case 2:
insert(&q,x);
braek;
case 3:
m=remove(&q);
printf("%d",m);
break;
case 4:
diplay(q);
break;
case 5:printf("bye ^_^");
getch();
}while(x!=5)
}
}
}

can you copy the into your compiler and try it ??

What warnings and errors are you getting?

Have you reviewed this code? Doesn't line 80, for instance, look funny to you?

This bears an awfully close resemblance to some code I just found on the internet.

OK for the first one, line 24 should be

Code:

    if(isempty(q))

Since q is already a pointer. You might consider "hungarian" style notation where you prefix pointer names with a p, in this case instead of "struct cQueue *q", you would use "struct cQueue *pq".

Also you can typedef to avoid having to keep using "struct" everywhere in your code. The microsoft convention for C is to prefix struct names with _ and to use uppercase for defines, typedefs, ...

Code:

typedef struct _CQUEUE
{ 
int front,rear; 
int items[max]; 
}CQUEUE, *PCQUEUE;

/* ... */

int isempty(PCQUEUE pq) /* pq is ptr to CQUEUE type */
{ 
/* ... */
}