栈(C语言版,尾插法,使用头节点)

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

typedef struct Node {
    int data;
    struct Node *pNext;
}NODE, *PNODE;

typedef struct Stack {
    PNODE pTop;
    PNODE pBottom;
}STACK, *PSTACK;

void init(PSTACK pS);
bool push(PSTACK, int);
bool is_empty(PSTACK);
void traverse(PSTACK);
bool pop(PSTACK, int *);

bool pop(PSTACK pS, int *pVal)
{
    if (is_empty(pS))
        return false;

    *pVal = pS->pTop->data;

    PNODE q = pS->pTop;
    pS->pTop = q->pNext;
    free(q);
    q = NULL;

    return true;
}

void traverse(PSTACK pS)
{
    PNODE p = pS->pTop;
    if (is_empty(pS)) {
        printf("stack is empty.\n");
        return;
    }

    while (p->pNext != NULL) {
        printf("%d ", p->data);
        p = p->pNext;
    }
    printf("\n");
}

bool is_empty(PSTACK pS)
{
    if (pS->pTop == pS->pBottom)
        return true;
    return false;
}

bool push(PSTACK pS, int val)
{
    PNODE pNew =  (PNODE)malloc(sizeof(NODE));
    if (NULL == pNew) {
        printf("内存分配失败");
        return false;
    }
    pNew->data = val;
    pNew->pNext = pS->pTop;

    pS->pTop = pNew;

    return true;
}

void init(PSTACK pS)
{
    PNODE pNew =  (PNODE)malloc(sizeof(NODE));
    if (NULL == pNew) {
        printf("内存分配失败");
        exit(-1);
    }
    pNew->pNext = NULL;

    pS->pTop = pS->pBottom = pNew;
}

int main(void)
{
    STACK S;
    init(&S);
    push(&S, 11);
    push(&S, 22);
    push(&S, 33);
    traverse(&S);

    int val;
    while (pop(&S, &val)) {
        printf("出栈成功:%d,栈内剩余:\n", val);
        traverse(&S);
    }

    return 0;
}

output:

[root@8be225462e66 c]# gcc stack_hb.c && ./a.out
33 22 11
出栈成功:33,栈内剩余:
22 11
出栈成功:22,栈内剩余:
11
出栈成功:11,栈内剩余:
stack is empty.
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