> For the complete documentation index, see [llms.txt](https://nitinranganath.gitbook.io/data-structures/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nitinranganath.gitbook.io/data-structures/queue/queue-using-array.md).

# Queue using Array

### Queue Structure :

```c
struct Queue {
    int size;
    int front;
    int rear;
    int *data;
};
```

### Creating a Queue Dynamically :

```c
struct Queue *createQueue(int size) {

    // Allocating memory for queue
    struct Queue *queue;
    queue = (struct Queue *)malloc(sizeof(struct Queue));
    
    // Set size, front and rear
    queue -> size = size;
    queue -> front = -1;
    queue -> rear = -1;
    
    // Allocating memory for array
    queue -> data = (int *)malloc(size * sizeof(int));
    
    return queue;

}
```

### Function to Check if Queue is Empty or Full :

```c
int isEmpty(struct Queue *queue) {
    return queue -> front == queue -> rear;
}

int isFull(struct Queue *queuevoid display(struct Queue *queue) {
  return queue -> rear == queue -> size - 1;
}
```

### En-queue Function :

```c
void enqueue(struct Queue *queue, int data) {

    if (isFull(queue)) {
        printf("Queue overflow !\n");
        return;
    }
    queue -> rear++;
    queue -> data[queue -> rear] = data;

}
```

### De-queue Function :

```c
int dequeue(struct Queue *queue) {

    if (isEmpty(queue)) {
        printf("Queue underflow !\n");
        return -1;
    }
    queue -> front++;
    int deletedValue = queue -> data[queue -> front];
    return deletedValue;

}
```

### Display Function :

```c
void display(struct Queue *queue) {

    for (int i = queue -> front + 1; i <= queue -> rear; i++) {
        printf("%d\t", queue -> data[i]);
    }
    printf("\n");

}
```

Contributed by Nitin Ranganath


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://nitinranganath.gitbook.io/data-structures/queue/queue-using-array.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.