estructura de datos | pila encadenada

1. Definición de la estructura de datos

typedef char StackType;
typedef struct StackNode {
    StackType data;
    struct StackNode* next;
}StackNode;

typedef struct {
    StackNode* top;
}LinkStack;

2. Resumen del método

void InitStack(LinkStack* S);//初始化栈
int IsStackEmpty(LinkStack S);//判断栈是否为空
int PushStack(LinkStack* L, StackType data);//入栈
int PopStack(LinkStack* L, StackType* data);//出栈
int GetStackTop(LinkStack* L, StackType* x);//取栈顶元素
int DestroyStack(LinkStack* L);//销毁栈

3. Explicación detallada del método

//初始化栈
void InitStack(LinkStack* S) {
    S->top = (StackNode*)malloc(sizeof(StackNode)); // 分配头节点
    S->top = NULL; //初始化为空
}
//判断栈是否为空
int IsStackEmpty(LinkStack S) {
    if (S.top == NULL) return 1;
    else return 0;
}
//入栈
int PopStack(LinkStack* L, StackType* data) {
    StackNode* del;
    if (L->top == NULL)	return -1;
    else {
        del = L->top;
        *data = del->data;
        L->top = L->top->next;
        free(del);
        return 0;
    }
}
//出栈
int PushStack(LinkStack *L, StackType data) {
    StackNode* news = (StackNode*)malloc(sizeof(struct StackNode));
    if (news == NULL)	return -1;
    else {
        news->data = data;
        news->next = L->top;
        L->top = news;
        return 0;
    }
}
//取栈顶元素
int GetStackTop(LinkStack* L, StackType* x) {
    if (L->top == NULL) {
        *x = NULL;
        return -1;
    }
    else {
        *x = L->top->data;
        return 1;
    }
}
//销毁栈
int DestroyStack(LinkStack* L){
    int cnt = 0;
    if (L == NULL)	return 0;
    struct StackNode* p = L->top, * q;
    free(L);
    while (p->next != NULL){
        q = p->next;
        cnt++;
        free(p);
        p = q;
    }
    return cnt;
}

4. Ejecución de resultados

        El código del método principal es el siguiente:

int main(void) {
    LinkStack S;
    InitStack(&S);
    
    PushStack(&S, 'a');

    if (IsStackEmpty(S) == 1) {
        printf("stack is null\n");
    }
    else {
        printf("stack is not null\n");
    }

    char a;
    if (PopStack(&S, &a) == -1) {
        printf("the stack is null,pop fails"); 
    }
    else {
        printf("%c", a);
    }
}

        El resultado de la operación es el siguiente:

5. Código fuente

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

typedef char StackType;
typedef struct StackNode {
    StackType data;
    struct StackNode* next;
}StackNode;

typedef struct {
    StackNode* top;
}LinkStack;

void InitStack(LinkStack* S);//初始化栈
int IsStackEmpty(LinkStack S);//判断栈是否为空
int PushStack(LinkStack* L, StackType data);//入栈
int PopStack(LinkStack* L, StackType* data);//出栈
int GetStackTop(LinkStack* L, StackType* x);//取栈顶元素
int DestroyStack(LinkStack* L);//销毁栈

//初始化栈
void InitStack(LinkStack* S) {
    S->top = (StackNode*)malloc(sizeof(StackNode)); // 分配头节点
    S->top = NULL; //初始化为空
}
//判断栈是否为空
int IsStackEmpty(LinkStack S) {
    if (S.top == NULL) return 1;
    else return 0;
}
//入栈
int PopStack(LinkStack* L, StackType* data) {
    StackNode* del;
    if (L->top == NULL)	return -1;
    else {
        del = L->top;
        *data = del->data;
        L->top = L->top->next;
        free(del);
        return 0;
    }
}
//出栈
int PushStack(LinkStack *L, StackType data) {
    StackNode* news = (StackNode*)malloc(sizeof(struct StackNode));
    if (news == NULL)	return -1;
    else {
        news->data = data;
        news->next = L->top;
        L->top = news;
        return 0;
    }
}
//取栈顶元素
int GetStackTop(LinkStack* L, StackType* x) {
    if (L->top == NULL) {
        *x = NULL;
        return -1;
    }
    else {
        *x = L->top->data;
        return 1;
    }
}
//销毁栈
int DestroyStack(LinkStack* L){
    int cnt = 0;
    if (L == NULL)	return 0;
    struct StackNode* p = L->top, * q;
    free(L);
    while (p->next != NULL){
        q = p->next;
        cnt++;
        free(p);
        p = q;
    }
    return cnt;
}


int main(void) {
    LinkStack S;
    InitStack(&S);
    
    PushStack(&S, 'a');

    if (IsStackEmpty(S) == 1) {
        printf("stack is null\n");
    }
    else {
        printf("stack is not null\n");
    }

    char a;
    if (PopStack(&S, &a) == -1) {
        printf("the stack is null,pop fails"); 
    }
    else {
        printf("%c", a);
    }
}