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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define EFULL 2
#define EMPTY 3
/* Queue stuff */
typedef struct {
int head;
int tail;
int len;
int cap;
int *buff;
} queue_t;
/* Queue functions */
int queue_init(queue_t *q, size_t cap) {
/* Make the struct and set i to zero */
memset(q, 0, sizeof(queue_t));
/* Allocate the buffer */
q->buff = (int *) malloc(cap * sizeof(int));
if( q->buff == NULL ) {
return 1;
}
/* Set capacity, the rest should be zero form memset */
q->cap = cap;
return 0;
}
void queue_free(queue_t *q) {
/* Free the heap buffer */
free(q->buff);
}
int queue_place(queue_t *q, int val) {
/* Check if full */
printf("len: %d\n", q->len);
if( q->len >= q->cap) {
printf("ERR: Full\n");
return EFULL;
}
/* Add to queue */
q->buff[q->head] = val;
/* Increase values */
q->head = (q->head+1) % q->cap;
q->len++;
return 0;
}
int queue_get(queue_t *q, int *val) {
/* Check if empty */
if( !q->len ) {
printf("ERR: Empty\n");
return EMPTY;
}
/* Read value */
if( val != NULL ){
*val = q->buff[q->tail];
}
/* Decrease values */
q->tail = (q->tail+1) % q->cap;
q->len--;
return 0;
}
int main(void) {
int in;
char com;
queue_t q;
queue_init(&q, 16);
for(;;) {
/* Read a command */
scanf("%c", &com);
if( com == 'w') {
printf("> ");
scanf("%d", &in);
queue_place(&q, in);
} else if( com == 'r' ) {
queue_get(&q, &in);
printf("%d\n", in);
} else if( com == 'q' ) {
break;
}
}
queue_free(&q);
}
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