Hello.
Could you provide some directions how would i make a class that would be a int holder. but i could retrieve data as "int" or "std::string" using overloads
exzample
my_custom_int value;
value = 0; //valid
value = 's';//invalid
value = "asd";//invalid
std::string string;
string = "asd"; //valid
string = value; // this to be valid
The last case to be valid what i need to do?
class MyIntWrapper
{
public:
MyIntWrapper():value(0) { }
explicit MyIntWrapper(int value):value(value) { }
operator int() const { return value; }
operator std::string() const { return boost::lexical_cast<std::string>(value); }
private:
int value;
};
Note how the standard library could allow such a conversion from std::string to const char *, but chooses not to. Conversion operators are hidden and can introduce subtle bugs. Providing an explicit str() method would be preferred.
Note how the standard library could allow such a conversion from std::string to const char *, but chooses not to. Conversion operators are hidden and can introduce subtle bugs. Providing an explicit str() method would be preferred.
That would be good enough.
What i don't know what i am looking for, in term of programing.
I cant find with Google a tutorial that would show how to make a "class int" with all functions it currently poses.
I really hate do make std::stringstream name.
then feed it int data.
then use it as .str()
then when i want to reuse it i need to clean it.
example
//I want
my_int a = 0;
a = unit.attack_power;
my_text.setText(a.str());
//I have
my_int a = 0;
a = unit.attack_power;
std::stringstream conv_attack_power;
conv_attack_power << a;
my_text.setText(conv_attack_power.str());
EDIT:: Note i don't want to replace the standard int i want to make a new class when i require this kind of usage.
Helper functions will simplify even further:
void setNumber(TextWidget &widget, int number) {
// As BitMaster says, this int/string conversion logic could be moved elsewhere
std::stringstream stream;
stream << number;
widget.setText(stream.str());
}
// Later
setNumber(my_test, unit.attack_power);
Helper functions will simplify even further:
void setNumber(TextWidget &widget, int number) { // As BitMaster says, this int/string conversion logic could be moved elsewhere std::stringstream stream; stream << number; widget.setText(stream.str()); } // Later setNumber(my_test, unit.attack_power);
i am thinking about something more like
std::string int_to_string(int value)
{
std::stringstream conv;
conv << value;
return conv.str();
}
// usage
OutputText(unit.name + " " + int_to_string(unit.attack_power) + "is over 9000");
I have so much happening and thinking about so many stuff.
Much thanks on help!
value = 0; //valid
value = 's';//invalid
I see a problem with these two lines. How do you have a class that accepts 0 (an int) and rejects 's' (an int)?
value = 0; //valid value = 's';//invalidI see a problem with these two lines. How do you have a class that accepts 0 (an int) and rejects 's' (an int)?
's' is a char in C++, so you'd need a function that takes a char and produces an error when passed something other than a digit. Or just always produces an error.
C++11 introduced some new conversion functions for that exact purpose:
std::to_string() - Integers and float-types to std::string.
Also:
std::stoi() - std::string to int
std::stol() - std::string to long
std::stoul() - std::string to unsigned long
std::stof() - std::string to float
std::stod() - std::string to double
The function-name format is:
stof
s <to> f
string <to> float
Just like the pre-existing atoi() (where 'a' is for ASCII, 'char*' raw-string functions)
This is different from strtof() and the like. I have no clue what those functions do. 
([Edit:] Ah, here's an explanation of strtof. I never knew about that function)
