c语言队列和栈的实现

在平时写OJ的题目的过程中，发现有很地方用到了队列和栈，但是c语言不像c++有stl库可以调用

于是这里手工实现了队列和栈，方便平时刷题使用：

队列的实现：

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

// you can define youself struct
// for example :
// typedef struct Position {
//     int x;
//     int y;
// } Element;
typedef int Element;
#define MAX_QUEUE_LENGTH 10

struct Queue {
    Element queue[MAX_QUEUE_LENGTH];
    int front;
    int rear;
    int length;
};

void Init(struct Queue* queue)
{
    memset(queue->queue, 0, sizeof(Element) * MAX_QUEUE_LENGTH);
    queue->front = 0;
    queue->rear = MAX_QUEUE_LENGTH - 1;
    queue->length = 0;
}

int Empty(struct Queue* queue)
{
    return queue->length == 0;
}

void Push(struct Queue* queue, Element elem)
{
    if (queue->length == MAX_QUEUE_LENGTH) {
        return;
    } else {
        queue->rear++;
        if (queue->rear == MAX_QUEUE_LENGTH) {
            queue->rear = 0;
        }
        queue->queue[queue->rear] = elem;
        queue->length++;
    }
}

void Pop(struct Queue* queue)
{
    if (queue->length == 0) {
        return;
    } else {
        queue->front++;
        if (queue->front == MAX_QUEUE_LENGTH) {
            queue->front = 0;
        }
        queue->length--;
    }
}

Element Front(struct Queue* queue)
{
    return queue->queue[queue->front];
}

// following is test code, you can use like this:
// int main()
// {
//     struct Queue queue;
//     Init(&queue);
//     for (int i = 0; i < 120; i++) {
//         Push(&queue, i);
//     }
//     while (!Empty(&queue)) {
//         int t = Front(&queue);
//         printf("%d\n", t);
//         Pop(&queue);
//     }
//     return 0;
// }

栈的实现：

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

// you can define youself struct
// for example :
// typedef struct Position {
//     int x;
//     int y;
// } Element;
typedef int Element;
#define MAX_STACK_LENGTH 10

struct stack {
    Element stack[MAX_STACK_LENGTH];
    int length;
};

void Init(struct stack* stack)
{
    memset(stack->stack, 0, sizeof(Element) * MAX_STACK_LENGTH);
    stack->length = 0;
}

int Empty(struct stack* stack)
{
    return stack->length == 0;
}

void Push(struct stack* stack, Element elem)
{
    if (stack->length == MAX_STACK_LENGTH) {
        return;
    } else {
        stack->stack[stack->length++] = elem;
    }
}

void Pop(struct stack* stack)
{
    if (stack->length == 0) {
        return;
    } else {
        stack->length--;
    }
}

Element Top(struct stack* stack)
{
    return stack->stack[stack->length - 1];
}

// following is test code, you can use like this:
// int main()
// {
//     struct stack stack;
//     Init(&stack);
//     for (int i = 0; i < 120; i++) {
//         Push(&stack, i);
//     }
//     while (!Empty(&stack)) {
//         int t = Top(&stack);
//         printf("%d\n", t);
//         Pop(&stack);
//     }
//     return 0;
// }