Stack.hpp
#pragma once
template <class T>
class Stack{
private:
T* _array;
size_t _capacity;
int _topindex;
public:
Stack() //構造函數
:_array(0)
, _capacity(0)
, _topindex(-1)
{}
void Push(const T& x){ //入棧操作
if (_topindex + 1 == _capacity){
_capacity = 2 * _capacity + 3;
T* tmp = new T[_capacity];
if (tmp == NULL){
cout << "failed new" << endl;
exit(-1);
}
memcpy(tmp, _array, sizeof(T) * (_topindex + 1));
delete _array;
_array = tmp;
}
_array[++_topindex] = x;
}
void Pop(){ //出棧
if (_topindex > -1){
//cout << _array[_topindex] << endl;
_topindex--;
}
}
bool empty(){ //清空
return _topindex = -1;
}
const T& top(){ //取棧頂元素
//cout << _array[_topindex] << endl;
return _array[_topindex];
}
};
main.cpp
#include<iostream>
#include<string>
#include"Stack.hpp"
using namespace std;
enum Type{
ADD,
SUB,
MUL,
DIV,
OP_NUM,
};
struct Cell{
Type _type;
int num;
};
Cell RPNExp[] = {
OP_NUM, 12,
OP_NUM, 3,
OP_NUM, 4,
ADD, 1,
MUL, 1,
OP_NUM, 6,
SUB, 1,
OP_NUM, 8,
OP_NUM, 2,
DIV, 1,
ADD, 1,
};
int main(){
Stack<int> s2;
int i = 0;
for (int i = 0; i < sizeof(RPNExp) / sizeof(RPNExp[0]);i++){ //取出元素
int left, right; //兩個操作數
switch (RPNExp[i]._type){ //將棧中數據出棧
case ADD: //如果是加號，取兩個操作數
left = s2.top();
s2.Pop();
right = s2.top();
s2.Pop();
s2.Push(left + right); //新的值入棧
break;
case SUB: //如果是減號，取兩個操作數
left = s2.top();
s2.Pop();
right = s2.top();
s2.Pop();
s2.Push(right - left);
break;
case MUL: //如果是乘號，取兩個操作數
left = s2.top();
s2.Pop();
right = s2.top();
s2.Pop();
s2.Push(left * right);
break;
case DIV: //如果是除號，取兩個操作數
left = s2.top();
s2.Pop();
right = s2.top();
s2.Pop();
s2.Push(right / left);
break;
case OP_NUM: //如果數字，入棧
s2.Push(RPNExp[i].num);
break;
default:
return -1;
}
}
cout << s2.top() << endl;
return 0;
}