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c code for stack using queue.

July ,7th ,2022

cstack_using_queue

write a c code for stack using queue.

A queue data structure is given with enqueue and dequeue operations. WAP to implement a stack using instances of queue data structure and operations on them

Code

#include <stdio.h>
#include <stdlib.h>

struct queue
{
    int size;
    int f;
    int r;
    int *arr;
};

int isEmpty(struct queue *q)
{
    if (q->r == q->f)
    {
        return 1;
    }
    return 0;
}

int isFull(struct queue *q)
{
    if (q->r == q->size - 1)
    {
        return 1;
    }
    return 0;
}

void enqueue(struct queue *q, int val)
{
    if (isFull(q))
    {
        printf("This Queue is full\n");
    }
    else
    {
        q->r++;
        q->arr[q->r] = val;
    }
}

int dequeue(struct queue *q)
{
    int a = -1;
    if (isEmpty(q))
    {
        printf("This Queue is empty\n");
    }
    else
    {
        q->f++;
        a = q->arr[q->f];
    }
    return a;
}

void push(struct queue *q, int val)
{
    if (isFull(q))
    {
        printf("Stack Overflow! Cannot push %d to the Stack\n", val);
    }
    else
    {
        enqueue(q, val);
    }
}

int pop(struct queue *q)
{
    struct queue qT;
    qT.size = q->size-1;
    qT.f = qT.r = 0;
    qT.arr = (int *)malloc(qT.size * sizeof(int));
    int x;
    if (isEmpty(q))
    {
        printf("Stack Underflow! Cannot pop from the stack\n");
        exit(0);
    }
    int z=q->r;
    while (q->f < q->r)
    {
        x = dequeue(q);
        enqueue(&qT, x);
    }
    q->f = q->r = 0;
    qT.r--;
    while (qT.f != qT.r)
    {
        int l = dequeue(&qT);
        enqueue(q, l);
    }
    return z;
}

int main()
{
    struct queue q;
    int s;
    printf("enter the size of queue : ");
    scanf("%d", &s);
    q.size = s;
    q.f = q.r = 0;
    q.arr = (int *)malloc(q.size * sizeof(int));
    printf("queue has been created successfully\n");

    push(&q, 1);
    push(&q, 2);
    push(&q, 3);

    printf("poped element is : %d\n", pop(&q));
    printf("poped element is : %d\n", pop(&q));
    printf("poped element is : %d\n", pop(&q));
    return 0;
}