Is this claim correct: "Anywhere you pass in a function, you can pass in a functor"?
for example:Code:bool cmp_function(int a, int b){
return a<b;
}
struct cmp_functor{
bool operator()(int a, int b){
return a<b;
}
};
std::sort(vec.begin(), vec.end(), cmp_function);
std::sort(vec.begin(), vec.end(), cmp_functor);
no, that is incorrect. but you can often structure your code in a way that allows either to be used. for example:
Code:template <typename Function>
void
foo(Function callback, int data)
{
callback(data);
}
void
bar(int)
{ }
struct baz
{
void
operator () (int)
{ }
};
foo(bar, 1);
foo(baz(), 1);
Thank you, I am curious why "baz()" should carry "()". Isn't "baz" enough?
Also, in your example, what would the 2 signatures be if the foo only accepts function or funcotr?
> I am curious why "baz()" should carry "()". Isn't "baz" enough?
Because baz is an object that needs to be instantiated, just like other classes or structs in C++.
> what would the 2 signatures be if the foo only accepts function or funcotr?
The simplest of the possibilities is probably
void foo( void (*callback )( int ), int data );
void foo( baz callback, int data );