数据结构与算法：栈 C语言实现

栈是仅在表尾进行插入、删除操作的线性表。即栈 S= (a1, a2, a3, ………,an-1, an)，其中表尾称为栈顶 /top，表头称为栈底/base。

由于只能在表尾进行操作，因此栈的运算规则就是“后进先出”(LIFO)

和线性表类似，栈也有两种存储结构——顺序栈与链栈

1.顺序栈的C语言实现

#include 
#include 

typedef struct Stack {
    int *data;//数据域
    int size;//栈长度,也是栈顶数组下标-1
    int max;//栈最大容量
} Stack;
//初始化
Stack *initStack(int max)
{
    struct Stack *stack;
    stack = (struct Stack *)malloc(sizeof(struct Stack));
    stack->size = 0;
    stack->max = max;
    stack->data = (int*)malloc(sizeof(int)*max);
    return stack;
}
//压栈
void push(Stack *stack, int item)
{
    if (stack->size >= stack->max)
    {
        printf("stack is full! \n");
    }else{
        stack->data[stack->size++] = item;
    }    
}
//出栈
int pop(Stack *stack)
{
    if (stack->size >= 0)
    {
        return stack->data[--stack->size];
    }
}
//test
int main()
{
    struct Stack *stack;
    stack = initStack(3);
    push(stack,1);
    push(stack,2);
    push(stack,3);
    push(stack,4);
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    push(stack,5);
    push(stack,6);
    push(stack,7);    
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    return 0;
}

测试效果：

2.链栈的C语言实现

本想偷懒，算了，还是写一遍吧，区别只是用链表去代替了数组，其实还不如数组方便省事一。一，但是可以无限长，，，

#include 
#include 

typedef struct StackNode {
    int data;//数据域
    struct StackNode *next;//指针域,这里用next或者pre都行，看怎么规定左右了，如果是左进左出那就是next，右进右出就是pre好理解
} StackNode;

typedef struct LinkedStack {
    int size;//栈长度
    int max;//栈最大容量
    struct StackNode *top;//指针域
} LinkedStack;

//初始化
LinkedStack *initStack(int max)
{
    struct LinkedStack *stack;
    stack = (struct LinkedStack *)malloc(sizeof(struct LinkedStack));
    stack->size = 0;
    stack->max = max;
    stack->top = NULL;
    return stack;
}
//压栈
void push(LinkedStack *stack, int item)
{
    if (stack->size >= stack->max)
    {
        printf("stack is full! \n");
    }else{
        struct StackNode *node;
        node = (struct StackNode *)malloc(sizeof(struct StackNode));
        node->data = item;
        node->next = stack->top;
        stack->size++;
        stack->top = node;
    }
}
//出栈
int pop(LinkedStack *stack)
{
    if (stack->size > 0)
    {
        struct StackNode *top;
        top = stack->top;
        stack->top = top->next;
        stack->size--;
        return top->data;
    }
}
int main()
{
    struct LinkedStack *stack;
    stack = initStack(3);
    push(stack,1);
    push(stack,2);
    push(stack,3);
    push(stack,4);
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    push(stack,5);
    push(stack,6);
    push(stack,7);
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    printf("stack out:%d \n", pop(stack));
    return 0;
}