和老师一样的代码，为啥是不匹配呢

#include<iostream>

#include"MyStack.h"

using namespace std;

int main()

{

MyStack<char> *pStack=new MyStack<char>(30);

MyStack<char> *pNeedStack=new MyStack<char>(30);

char str[]="[()]";

char currentNeed=0;

for(int i=0;i<strlen(str);i++)

{

if(str[i]!=currentNeed)

{

pStack->push(str[i]);

switch(str[i])

{

case'[':

if(currentNeed!=0)

{

pStack->push(currentNeed);

}

currentNeed=']';

break;

case'(':

if(currentNeed!=0)

{

pStack->push(currentNeed);

}

currentNeed=')';

break;

default:

cout<<"不匹配"<<endl;

system("pause");

return 0;

}

}

else

{

char elem;

pStack->pop(elem);

if(!pNeedStack->pop(currentNeed))

{

currentNeed=0;

}

}

}

if(pStack->stackEmpty())

{

cout<<"匹配"<<endl;

}

else

cout<<"不匹配"<<endl;

delete pStack;

pStack=NULL;

delete pNeedStack;

pNeedStack=NULL;

system("pause");

return 0;

}

求大神指点