IEEExtreme 2013

rpnhexcalc.cpp

#include <algorithm>
#include <functional>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <map>
#include <stack>
#include <vector>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

struct underflow{};
struct overflow{};

int add(int first, int second)
{
  if(first + second > 65535)
    return 65535;
  else
    return first + second;
}
 
int subtract(int first, int second)
{
  if(first > second)
    return 0;
  else
    return second - first;
}

int mand(int first, int second)
{
  return (first & second);
}

int mor(int first, int second)
{
  return first | second;
}

int mxor(int first, int second)
{
  return first xor second;
}

int bnot(int u)
{
  return (~u - 0xFFFF0000);
}

map<string, function<int(int,int)>> binaryMap; 
map<string, function<int(int)>> unaryMap; 

int operatorP(string word)
{
  if(binaryMap.find(word) != binaryMap.end())
    return 2;
  if(unaryMap.find(word) != unaryMap.end())
    return 1;
  return 0;
  
}

int main()
{
  stack<string> tokens;

  
  binaryMap["+"] = add;
  binaryMap["-"] = subtract;
  binaryMap["&"] = mand;
  binaryMap["|"] = mor;
  binaryMap["X"] = mxor;
    
  unaryMap["~"] = bnot;

  string sentence;
  getline(cin, sentence);
  
  vector<string> words;
  words.push_back("");
  for(int i = 0; i < sentence.length(); i++)
    {
      if(sentence[i] == '\n')
	break;

      if(sentence[i] == ' ')
	{
	  words.push_back("");
	}
      else
	{
	  words.back() += sentence[i];
	}
    }

  stack<string> wordsStack;
  stringstream ss;
  stringstream sss;
  try
    {
      for(auto tWord = words.begin(); tWord != words.end(); tWord++)
	{
	  int numberConsume;
	  if(numberConsume = operatorP(tWord->c_str()))
	    {
	      if(numberConsume > wordsStack.size())
		{
		  throw exception();
		}
	      if(numberConsume == 1)
		{
		  int val1 = atoi(wordsStack.top().c_str());
		  ss.clear();

		  ss << wordsStack.top();
		  ss >> val1;

		  wordsStack.pop();
		  wordsStack.push(to_string(unaryMap[*tWord](val1)));
		}
	      else
		{
		  int val1;
		  ss.clear();

		  ss << wordsStack.top();
		  ss >> val1;
		  wordsStack.pop();

		  int val2;
		  ss.clear();

		  ss << wordsStack.top();
		  ss >> val2;
		  wordsStack.pop();

		  wordsStack.push(to_string(binaryMap[*tWord](val1, val2)));
		}
	    }
	  else
	    {
	      int s;

	      sss.clear();
	      sss << hex << *tWord;
	      sss >> s;

	      wordsStack.push(to_string(s));
	    }
	}
      if(wordsStack.size() > 1)
	cout << "ERROR" << endl;
      else
	cout << uppercase << setfill('0') << setw(4) << hex << atoi(wordsStack.top().c_str()) << endl;
    }
  catch(underflow& und)
    {
      cout << "0000" << endl;
    }
  catch(overflow& und)
    {
      cout << "FFFF" << endl;
    }
  catch(exception& e)
    {
      cout << "ERROR" << endl;
    }
  
  return 0;
}

A lot of the exceptions aren't used because the problem was open to interpretation.