no instance of function template "std::make_pair" matches the argument list

[masterinex]

When i run the code i get the following errors:

Severity Code Description Project File Line Suppression State
Error (active) E0304 no instance of function template "std::make_pair" matches the argument list ExpressionParser


Severity Code Description Project File Line Suppression State
Error C2664 'std::pair<int,int> std::make_pair<int,int>(_Ty1 &&,_Ty2 &&)': cannot convert argument 2 from 'const int' to 'int &&' ExpressionParser

#include <iostream>
#include <sstream>
#include <list>
#include <stack>
#include <map>
#include <string>
#include <vector>
#include <iterator>
#include <stdlib.h>

#include <utility>
#include <functional>



const int LEFT_ASSOC = 0;
const int RIGHT_ASSOC = 1;

// Map the different operators: +, -, *, / etc  
typedef std::map< std::string, std::pair< int, int >> OpMap;
typedef std::vector<std::string>::const_iterator cv_iter;
typedef std::string::iterator s_iter;

const OpMap::value_type assocs[] =
{ OpMap::value_type("+", std::make_pair<int,int>(0, LEFT_ASSOC)),
OpMap::value_type("-", std::make_pair<int,int>(0, LEFT_ASSOC)),
OpMap::value_type("*", std::make_pair<int,int>(5, LEFT_ASSOC)),
OpMap::value_type("/", std::make_pair<int,int>(5, LEFT_ASSOC)) };

const OpMap opmap(assocs, assocs + sizeof(assocs) / sizeof(assocs[0]));

// Test if token is an pathensesis  
bool isParenthesis(const std::string& token)
{
	return token == "(" || token == ")";
}

// Test if token is an operator        
bool isOperator(const std::string& token)
{
	return token == "+" || token == "-" ||
		token == "*" || token == "/";
}

// Test associativity of operator token        
bool isAssociative(const std::string& token, const int& type)
{
	const std::pair<int, int> p = opmap.find(token)->second;
	return p.second == type;
}

// Compare precedence of operators.        
int cmpPrecedence(const std::string& token1, const std::string& token2)
{
	const std::pair<int, int> p1 = opmap.find(token1)->second;
	const std::pair<int, int> p2 = opmap.find(token2)->second;

	return p1.first - p2.first;
}

// Convert infix expression format into reverse Polish notation        
bool infixToRPN(const std::vector<std::string>& inputTokens,
	const int& size,
	std::vector<std::string>& strArray)
{
	bool success = true;

	std::list<std::string> out;
	std::stack<std::string> stack;

	// While there are tokens to be read    
	for (int i = 0; i < size; i++)
	{
		// Read the token    
		const std::string token = inputTokens[i];

		// If token is an operator        
		if (isOperator(token))
		{
			// While there is an operator token, o2, at the top of the stack AND    
			// either o1 is left-associative AND its precedence is equal to that of o2,    
			// OR o1 has precedence less than that of o2,    
			const std::string o1 = token;

			if (!stack.empty())
			{
				std::string o2 = stack.top();

				while (isOperator(o2) &&
					((isAssociative(o1, LEFT_ASSOC) && cmpPrecedence(o1, o2) == 0) ||
					(cmpPrecedence(o1, o2) < 0)))
				{
					// pop o2 off the stack, onto the output queue;                        
					stack.pop();
					out.push_back(o2);

					if (!stack.empty())
						o2 = stack.top();
					else
						break;
				}
			}

			// push o1 onto the stack.     
			stack.push(o1);
		}
		// If the token is a left parenthesis, then push it onto the stack.    
		else if (token == "(")
		{
			// Push token to top of the stack      
			stack.push(token);
		}
		// If token is a right bracket ')'        
		else if (token == ")")
		{
			// Until the token at the top of the stack is a left parenthesis,     
			// pop operators off the stack onto the output queue.    
			std::string topToken = stack.top();

			while (topToken != "(")
			{
				out.push_back(topToken);
				stack.pop();

				if (stack.empty()) break;
				topToken = stack.top();
			}

			// Pop the left parenthesis from the stack, but not onto the output queue.                              
			if (!stack.empty()) stack.pop();

			// If the stack runs out without finding a left parenthesis,     
			// then there are mismatched parentheses.                
			if (topToken != "(")
			{
				return false;
			}
		}
		// If the token is a number, then add it to the output queue.      
		else
		{
			out.push_back(token);
		}
	}

	// While there are still operator tokens in the stack:    
	while (!stack.empty())
	{
		const std::string stackToken = stack.top();

		// If the operator token on the top of the stack is a parenthesis,     
		// then there are mismatched parentheses.    
		if (isParenthesis(stackToken))
		{
			return false;
		}

		// Pop the operator onto the output queue./    
		out.push_back(stackToken);
		stack.pop();
	}

	strArray.assign(out.begin(), out.end());

	return success;
}


double RPNtoDouble(std::vector<std::string> tokens)
{
	std::stack<std::string> st;

	// For each token        
	for (int i = 0; i < (int)tokens.size(); ++i)
	{
		const std::string token = tokens[i];

		// If the token is a value push it onto the stack        
		if (!isOperator(token))
		{
			st.push(token);
		}
		else
		{
			double result = 0.0;

			// Token is an operator: pop top two entries        
			const std::string val2 = st.top();
			st.pop();
			const double d2 = strtod(val2.c_str(), NULL);

			if (!st.empty())
			{
				const std::string val1 = st.top();
				st.pop();
				const double d1 = strtod(val1.c_str(), NULL);

				//Get the result        
				result = token == "+" ? d1 + d2 :
					token == "-" ? d1 - d2 :
					token == "*" ? d1 * d2 :
					d1 / d2;
			}
			else
			{
				if (token == "-")
					result = d2 * -1;
				else
					result = d2;
			}


			// Push result onto stack       
			std::ostringstream s;
			s << result;
			st.push(s.str());
		}
	}

	return strtod(st.top().c_str(), NULL);
}

std::vector<std::string> getExpressionTokens(const std::string& expression)
{
	std::vector<std::string> tokens;
	std::string str = "";

	for (int i = 0; i < (int)expression.length(); ++i)
	{
		const std::string token(1, expression[i]);

		if (isOperator(token) || isParenthesis(token))
		{
			if (!str.empty())
			{
				tokens.push_back(str);
			}
			str = "";
			tokens.push_back(token);
		}
		else
		{
			// Append the numbers    
			if (!token.empty() && token != " ")
			{
				str.append(token);
			}
			else
			{
				if (str != "")
				{
					tokens.push_back(str);
					str = "";
				}
			}
		}
	}

	return tokens;
}

// Print iterators in a generic way
template<typename T, typename InputIterator>
void Print(const std::string& message,
	const InputIterator& itbegin,
	const InputIterator& itend,
	const std::string& delimiter)
{
	std::cout << message << std::endl;

	std::copy(itbegin,
		itend,
		std::ostream_iterator<T>(std::cout, delimiter.c_str()));

	std::cout << std::endl;
}

int main()
{
	std::string s = "( 1 + 2) * ( 3 / 4 )-(5+6)";

	Print<char, s_iter>("Input expression:", s.begin(), s.end(), "");

	// Tokenize input expression        
	std::vector<std::string> tokens = getExpressionTokens(s);

	// Evaluate feasible expressions  
	std::vector<std::string> rpn;
	if (infixToRPN(tokens, tokens.size(), rpn))
	{
		double d = RPNtoDouble(rpn);
		Print<std::string, cv_iter>("RPN tokens:  ", rpn.begin(), rpn.end(), " ");

		std::cout << "Result = " << d << std::endl;
	}
	else
	{
		std::cout << "Mis-match in parentheses" << std::endl;
	}

	return 0;

}


from http://www.technical-recipes.com/2011/a-mathematical-expression-parser-in-java-and-cpp/

[jlb]

Your second error message is giving you a real big hint:

Severity Code Description Project File Line Suppression State
Error C2664 'std::pair<int,int> std::make_pair<int,int>(_Ty1 &&,_Ty2 &&)': cannot convert argument 2 from 'const int' to 'int &&' ExpressionParser

Something appears to be a const int, not an int, perhaps you need to redo your make_pair templates?

By the way I'd be surprised if there were not several more messages involving this problem that further describe the problem, also you failed to provide the line numbers that your compiler should have provided as well.

In future please post all of the error messages exactly as they appear in your development environment.

[mbozzi]

In general, you should not explicitly specify template arguments when they could be deduced instead. The repetition (of the argument type) introduces potential bugs, and type and value-category mismatches may cause unnecessary copies and temporary materializations.

Indeed, std::make_pair relies on template argument deduction to handle perfect forwarding. Don't explicitly specify the template arguments, and your code will compile:

// std::make_pair<int, int>(0, LEFT_ASSOC) // error
std::make_pair(0, LEFT_ASSOC) // fine 

N.B.: std::forward is one important exception to the guideline. Such exceptions are relatively rare.

[Peter87]

The signature of std::make_pair has changed in order to handle perfect forwarding of the arguments. This unfortunately breaks some older codes. Your usage of std::make_pair seems to work fine in C++03 but breaks in C++11 and later.

The main purpose of using std::make_pair is so that the template arguments can be deduced. If you want to explicitly specify the types for some reason it's better to use the std::pair constructor.

std::pair<int, int>(0, LEFT_ASSOC)

[Peter87]

Note that nowadays you can often be less verbose by using {}-initialization.

const OpMap::value_type assocs[] =
{ {"+", {0, LEFT_ASSOC}},
  {"-", {0, LEFT_ASSOC}},
  {"*", {5, LEFT_ASSOC}},
  {"/", {5, LEFT_ASSOC}} };