C++指针

[hellobabay]

#include <iostream.h>
typedef struct stacknode
{
int point;
struct stacknode *next;
}StackNode;
typedef struct
{
StackNode *top;
}LinkStack;








void InitStack(LinkStack *s)
{
s->top=NULL;

}

bool StackEmpty(LinkStack *s)
{
if(s->top==NULL)
return true;
else
return false;
}

void Push(LinkStack *s, int p)
{
StackNode *oldtOP=s->top;
StackNode stackNode;
stackNode.point=p;
stackNode.next=oldtOP;
s->top=&stackNode;
cout<<s->top<<" ";
cout<<s->top->point<<" Push "<<endl;

}


void Pop(LinkStack *s)
{
cout<<s->top<< " ";
cout<<s->top->point<<" Pop "<<endl;
// StackNode *oldtOP=s->top;
// s->top=oldtOP->next;


}



void main()
{

LinkStack linkStack;
int start=5;
InitStack(&linkStack);
Push(&linkStack,start);
cout<<linkStack.top->point<<" ";
Pop(&linkStack);
}

为什么cout<<s->top->point<<" Push "<<endl;和cout<<s->top->point<<" Pop "<<endl;不是相同的值

[龙哥依旧]

#include <iostream>

using namespace std;

typedef struct stacknode
{
    int point;
    struct stacknode *next;
}StackNode;

typedef struct  
{
    StackNode *top;
}LinkStack;

void InitStack(LinkStack *s)
{
    s->top=NULL;
    
}

bool StackEmpty(LinkStack *s)
{
    if(s->top==NULL)
        return true;
    else
        return false;
}

void Push(LinkStack *s, int p)
{
    StackNode *oldtOP=s->top;
    StackNode *pstackNode = new StackNode;
    pstackNode->point=p;
    pstackNode->next=oldtOP;
    s->top=pstackNode;
    cout<<s->top<<" ";
    cout<<s->top->point<<" Push "<<endl;
}

void Pop(LinkStack *s)
{
    if(StackEmpty(s))
        return;
    
    StackNode *oldtOP = NULL;
    
    oldtOP=s->top; 
    s->top = s->top->next;
    
    cout<<oldtOP<<" "<<oldtOP->point<<" Pop "<<endl;
    
    delete oldtOP;
    oldtOP = NULL;
}

void main()
{
    LinkStack linkStack;
    
    InitStack(&linkStack);
    Push(&linkStack,5);
    Push(&linkStack,6);
    Push(&linkStack,7);
    Push(&linkStack,8);
    
    cout<<linkStack.top->point<<" \n";
    
    Pop(&linkStack);
}

局部变量函数运行完就没了，得动态申请内存。

[s_hhm]

二楼正解.在局部函数的所有变量,在函数执行完毕后,都得被释放.楼主那样做,没出错非法内存访问就不错了.

[quwei197874]

栈是后进先出