Eownnh - Online C Compiler & Debugging Tool

#include <stdio.h>

#define SIZE 5
int queue[SIZE];
int head, tail;

void enqueue(int value);
int dequeue(void);

int main(void)
{
    head = tail = 0;
    int resp, data, i;

    while(1){
        printf("1:enqueue 2:dequeue 0:end > ");
        scanf("%d", &resp);

        if(resp == 0) break;

        switch (resp){
            case 1:
                printf("enqueue(1): 'value' > ");
                scanf("%d", &data);
                enqueue(data);
                break;
            case 2:
                dequeue();
                break;
        }

        printf("head:%d, tail:%d\n", head, tail); // headとtailの現在位置を表示

        printf("queue:");
        if (head != tail) {
            i = head;
            while(i != tail){
                printf("queue[%d]=%d, ", i, queue[i]);
                i = (i + 1) % SIZE;
            }
        }
        printf("\n");
    }

    return 0;
}

void enqueue(int value)
{
    if (head == (tail+1)%SIZE) {
        printf("キューは満杯で入りませんでした\n");
    } else {
        queue[tail] = value;
        tail = (tail + 1) % SIZE;
    }
}

int dequeue(void)
{
    int value;
    if (head == tail) {
        printf("キューは空で取り出せませんでした\n");
        return 0; // またはエラー値
    } else {
        value = queue[head];
        head = (head + 1) % SIZE;
        return value;
    }
}