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queue.c
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queue.c
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/*
* Adapted from: https://www3.cs.stonybrook.edu/~skiena/392/programs/
*/
#include "queue.h"
#include <stdio.h>
void init_queue(struct Queue *q) {
q->first = 0;
q->last = QUEUESIZE-1;
q->count = 0;
}
void enqueue(struct Queue *q, int x) {
if (q->count >= QUEUESIZE)
printf("Warning: queue overflow enqueue x=%d\n",x);
else {
q->last = (q->last+1) % QUEUESIZE;
q->q[ q->last ] = x;
q->count = q->count + 1;
}
}
int dequeue(struct Queue *q) {
int x;
if (q->count <= 0) printf("Warning: empty queue dequeue.\n");
else {
x = q->q[ q->first ];
q->first = (q->first+1) % QUEUESIZE;
q->count = q->count - 1;
}
return(x);
}
bool empty(struct Queue *q) {
if (q->count <= 0) return (1);
else return (0);
}
void print_queue(struct Queue *q) {
int i;
i=q->first;
while (i != q->last) {
printf("%c ",q->q[i]);
i = (i+1) % QUEUESIZE;
}
printf("%2d ",q->q[i]);
printf("\n");
}