#include <iostream>
using namespace std;
#include <stack>
#include <assert.h>
enum Type
{
OP_SYMBOL,
OP_NUM,
ADD,
SUB,
MUL,
DIV,
};
struct Cell
{
Type _type;
int _value;
};
int CountRPN(Cell a[], size_t size)
{
assert(a != NULL);
stack<int> s;
while (size--)
{
if (a->_type == OP_NUM)
{
s.push(a->_value);
}
if (a->_type == OP_SYMBOL)
{
int right = s.top();
s.pop();
int left = s.top();
s.pop();
switch (a->_value)
{
case ADD:
s.push(left+right);
break;
case SUB:
s.push(left-right);
break;
case MUL:
s.push(left*right);
break;
case DIV:
s.push(left/right);
break;
default:
break;
}
}
++a;
}
return s.top();
}
void TestRPN()
{
Cell RPNArray[] =
{
{OP_NUM, 12},
{OP_NUM, 3},
{OP_NUM, 4},
{OP_SYMBOL, ADD},
{OP_SYMBOL, MUL},
{OP_NUM, 6},
{OP_SYMBOL, SUB},
{OP_NUM, 8},
{OP_NUM, 2},
{OP_SYMBOL, DIV},
{OP_SYMBOL, ADD},
};
cout<<CountRPN(RPNArray, sizeof(RPNArray)/sizeof(RPNArray[0]));
}
int main()
{
TestRPN();
return 0;
}