C 語言 資料結構 使用Linked list 建立堆疊(Stack)

小弟自我複習的程式碼~

#include<stdio.h>
#include<stdlib.h>
struct node{
    int data;
    struct node *next;
};
typedef struct node NODE;
NODE* push(NODE*,int);
NODE* pop(NODE*);
void print(NODE*);
int main() {
    NODE *top = NULL;
    int select,val;
    printf("==================\n");
    printf("<1> push data\n");
    printf("<2> pop data\n");
    printf("<3> top data\n");
    printf("<4> print stack\n");
    printf("<5> end\n");
    printf("==================\n");
    while(1) {
        printf("please select: ");
        scanf("%d",&select);
        switch(select) {
            case 1:
                printf("please enter a number: ");
                scanf("%d",&val);
                top  = push(top,val);
                break;
            case 2:
                top = pop(top);
                break;
            case 3:
                printf("stack top: %d\n",top->data);
                break;
            case 4:
                printf("stack content: ");
                print(top);
                printf("\n");
                break;
            case 5:
                return 0;
            default:
                printf("Please enter a correct number!\n");
        }
    }
}
NODE *push(NODE *top,int val) {
    NODE *newnode = (NODE*)malloc(sizeof(NODE));
    newnode->data = val;
    newnode->next = top;
    return newnode;
}
NODE *pop(NODE *top) {
    if(top == NULL) {
        printf("stack is empty!\n");
        return NULL;
    }       
    printf("Data %d has been deleted!\n",top->data);
    NODE *tempnode = top;
    top = top->next;
    free(tempnode);
    return top;
}
void print(NODE*top) {
    printf("top ");
    while(top != NULL) {
        printf("%d ",top->data);
        top = top->next;
    }
}

2021/12/12 更新:上傳程式碼