Template function not recognised

Question

I'm trying to write a set of functions which converts strings to their corresponding numeric value, "int, float, double..." but My templated function is not recognized by the c++ compiler.
When I call it, I get a message stating "No matching Function for call. I was returning a function of type T from this function, but I had this error message, I've tried modifying the function so it could change the value of a variable passed by reference, but the error persists.
I've tried modifying this function but it t doesnt still works please help. I have several versions of this function which are overriden, as follows:

static void convertValue(eOperandType type, const std::string &value, FloatOperandType typeDeterminer, T &container) { try { container = std::stof(value); } catch (std::invalid_argument e) { throw AVMException("The value passed as number is not valid"); } catch (std::out_of_range e) { char *msg = "The value passed is out of the range of the typed passed"; throw AVMException(msg); } catch (exception& e) { throw AVMException("An unexpected error occured when converting value types"); } } template <typename T> static void convertValue(eOperandType type, const std::string &value, IntOperandType typeDeterminer, T &container) { int val = 0; try { val = std::stoi(value); switch(type) { case eOperandType::Int8: if(val < -128 || val > 127) throw AVMWarnException("Overflow for type Int8"); case eOperandType::Int16: if(val < -32768 || val > 32,767) throw AVMWarnException("Overflow for type Int16"); case eOperandType::Int32: if(val < -2147483648 || val > 2147483647) throw AVMWarnException("Overflow for type Int32"); } container = std::stoi(value); } catch (std::invalid_argument e) { throw AVMException("The value passed as number is not valid"); } catch (std::out_of_range e) { char *msg = "The value passed is out of the range of the typed passed"; throw AVMException(msg); } catch (exception& e) { throw AVMException("An unexpected error occured when converting value types"); } }

Here is how I call the function:

 int v = 0; Converter::convertValue<int>("20", eOperandType::Int8, IntOperandType::_Int8, &v);

There are already functions in the standard library that achieve this (see atoi, atof and strtod). — iambrj
– iambrj, Commented Oct 26, 2018 at 17:41
From prototype your call should be Converter::convertValue<int>(eOperandType::Int8,"20", IntOperandType::_Int8, &v); and you forgot template <typename T> in the first function — PilouPili
– PilouPili, Commented Oct 26, 2018 at 17:46

alter_igel · Accepted Answer · 2018-10-26 17:55:12Z

If I may hazard a guess that eOperandType is an enum type, then it makes sense that you can't convert "20" to it. Additionally, you pass an int* where an int& is expected. Notice your function's signature:

template <typename T> void convertValue(eOperandType, const std::string&, IntOperandType, T&)

and compare this to how you call the function:

convertValue<int>("20", eOperandType::Int8, IntOperandType::_Int8, &v);

Here, your parameters have the following types:

const char[3], eOperandType, IntOperandType, int*

Notice the mismatch from the signature? You probably want to call it like this:

int v = 0; Converter::convertValue<int>(eOperandType::Int8, "20", IntOperandType::_Int8, v);

where "20" is implicitly convertible to const std::string& and v, which is an lvalue of type int, can be implicitly bound to an lvalue reference to int, int&.

Stuckatmarine · Accepted Answer · 2018-10-26 17:47:02Z

It could be the string coming before the e operand type when you call the function, the param lists do not match.

Collectives™ on Stack Overflow

Template function not recognised

2 Answers 2

Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Related