C++0x initializer list example
I would like to see how this example of existing code would be able to take advantage of the C++0x initializer list feature.
Example0:
#include <vector>
#include <string>
struct Ask {
std::string prompt;
Ask(std::string a_prompt):prompt(a_prompt){}
};
struct AskString : public Ask{
int min;
int max;
AskString(std::string a_prompt, int a_min, int a_max):
Ask(a_prompt), min(a_min), max(a_max){}
};
int main()
{
std::vector<Ask*> ui;
ui.push_back(new AskString("Enter your name: ", 3, 25));
ui.push_back(new AskString("Enter your city: ", 2, 25));
ui.push_back(new Ask("Enter your age: "));
}
Would it support something like this:
Example1:
std::vector<Ask*> ui ={
AskString("Enter your name: ", 3, 25),
AskString("Enter your city: ", 2, 25),
Ask("Enter your age: ")
};
Or must it have literals like this?:
Example2:
std::vector<Ask*> ui ={
{"Enter your name: ", 3, 25},
{"Enter your city: ", 2, 25},
{"Enter your age: "}
};
If so how would the difference between AskString and Ask be handled?
You last examples wouldn't be allowed as you ask for pointers but try to provide local temporary objects instead.
std::vector<Ask*> ui ={
new AskString{"Enter your name: ", 3, 25},
new AskString{"Enter your city: ", 2, 25},
new Ask{"Enter your age: "}
};
That would be allowed and there would be no type ambiguity.
That would be right too :
std::vector<Ask*> ui ={
new AskString("Enter your name: ", 3, 25),
new AskString("Enter your city: ", 2, 25),
new Ask("Enter your age: ")
};
And your example is more like :
std::vector<Ask> ui ={ // not pointers
{"Enter your name: "},
{"Enter your city: "},
{"Enter your age: "}
};
std::vector<AskString> uiString ={ // not pointers
{"Enter your name: ", 3, 25},
{"Enter your city: ", 2, 25},
{"Enter your age: ", 7, 42}
};
and again there would be no ambiguity on the types.
A c++ initializer list is homogenous, meaning it must have all the same type, so example #2 is out. If you used new in example 1, it would work.
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