Abdelrahman Said
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
// vim:fileencoding=utf-8:foldmethod=marker
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/* queue.c
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Implementation of a FIFO queue abstract data type.
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*/
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/* Copyright 2003-2020 by Steven S. Skiena; all rights reserved.
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Permission is granted for use in non-commerical applications
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provided this copyright notice remains intact and unchanged.
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These programs appear in my books:
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"The Algorithm Design Manual" by Steven Skiena, second edition, Springer,
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London 2008. See out website www.algorist.com for additional information
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or https://www.amazon.com/exec/obidos/ASIN/1848000693/thealgorith01-20
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"Programming Challenges: The Programming Contest Training Manual"
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by Steven Skiena and Miguel Revilla, Springer-Verlag, New York 2003.
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See our website www.programming-challenges.com for additional information,
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or https://www.amazon.com/exec/obidos/ASIN/0387001638/thealgorithmrepo/
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include "queue.h"
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void init_queue(queue *q) {
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q->first = 0;
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q->last = QUEUESIZE - 1;
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q->count = 0;
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}
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void enqueue(queue *q, item_type x) {
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if (q->count >= QUEUESIZE) {
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printf("Warning: queue overflow enqueue x=%d\n", x);
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} else {
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q->last = (q->last + 1) % QUEUESIZE;
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q->q[q->last] = x;
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q->count = q->count + 1;
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}
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}
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item_type dequeue(queue *q) {
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item_type x;
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if (q->count <= 0) printf("Warning: empty queue dequeue.\n");
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x = q->q[q->first];
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q->first = (q->first + 1) % QUEUESIZE;
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q->count = q->count - 1;
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return(x);
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}
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item_type headq(queue *q) {
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return(q->q[q->first]);
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}
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int empty_queue(queue *q) {
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if (q->count <= 0) {
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return (true);
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}
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return (false);
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}
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void print_queue(queue *q) {
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int i;
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i = q->first;
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while (i != q->last) {
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printf("%d ", q->q[i]);
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i = (i + 1) % QUEUESIZE;
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}
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printf("%2d ", q->q[i]);
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printf("\n");
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}
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