C中栈的数据结构

Question

我是结构的新手，我试图实现一个堆栈以及将数据推入堆栈并打印它们的操作。但是，我遇到了一些问题，请您帮我解决一下吗？

我使用了教程点提供的编译器，其中代码编译成功，但输出包含分段错误，我认为它存在于“PushNode”或“PrintStackData”中。

当我输出堆栈中的节点数（使用计数器）时，这个数字比正确的多一个，比如我输入了 5 个数据，但它打印出 6 个。

非常感谢！

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



//Define data node
typedef struct Node{
    int data; //Data of data node in Stack
    struct Node *Next;  // Pointer pointing to next data node or null
}NODE;

//Define head node for stack
typedef struct StackHead{
    int Counter;
    NODE *Top;
}STACKHEAD;

// function to create a blank stack
void CreateStack(STACKHEAD *Head){      
    Head= (STACKHEAD*)malloc(sizeof(STACKHEAD));
    Head->Counter=0;
    Head->Top = NULL;   
};

//Function to push a data node in stack
void PushNode(STACKHEAD *Head){

    NODE *pNew=(NODE*)malloc(sizeof(NODE)); //Must allocate memory to initialise it otherwise segmentation error.
    printf("Enter value for new data Node: ");
    scanf("%d",&(pNew->data));  //Assign input to data of new node

    if(Head->Top==NULL){
        pNew->Next=NULL;
    }
    else{
        pNew->Next=Head->Top;
    }
    Head->Top=pNew;
    Head->Counter++;
};

//Function to print out each data node in the Stack
void PrintStackData(STACKHEAD *Head){

    STACKHEAD *Position=(STACKHEAD*)malloc(sizeof(STACKHEAD));

    //Position->Top=Head->Top;
    Position = Head;

    printf("The data in the Stack is: ");
     while(Position->Top!=NULL){
         printf("%d, ",Position->Top->data);
         Position->Top= Position->Top->Next;
    }
}

int main()
{
    int numOfData; // Number of data that users want to insert into the stack
    STACKHEAD *Head; //Declare and initialise a new Stack Head
    CreateStack(Head); // Initialise the Stack

    printf("How many data do you want to insert to the Stack?");
    scanf("%d", &numOfData);

    for(int i=0;i<numOfData;i++){
        PushNode(Head);
    }
    printf("The data value of the top Node is %d\n", Head->Top->data);

    PrintStackData(Head);   //print out each data node in Stack using function.

    printf("\nThe number of data in the Stack is: %d\t", Head->Counter); 

    printf("\nThe data value of the top Node is %d\t", Head->Top->data);
    getchar();

}

Answer 1

当你调用 CreateStack 时，指针是按值传递的。函数中调用 malloc 返回的指针永远不会分配给堆栈头。

尝试编写一个 CreateStack 函数，该函数返回一个指向所创建堆栈的指针。它不应该带任何参数。