What's the difference between explicit and implicit assignment in C++

Question

int value = 5; // this type of assignment is called an explicit assignment
int value(5); // this type of assignment is called an implicit assignment

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Answer 1

Only the first one is an assignment. They are both initialization.

Edit: actually, I'm wrong. Neither are assignment.

Answer 2

Neither of these is an assignment of any kind -- they're both initialization. The first uses copy initialization, and the second direct initialization. (FWIW, I'm pretty sure I've never heard the terms "explicit assignment" or "implicit assignment" before).

Edit: (Mostly in response to Nathan's comment):

Here's a corrected version of the code from your comment:

#include <iostream>

struct Foo { 
    Foo() { 
        std::cout << "Foo::ctor()" << std::endl; 
    } 
    Foo(Foo const& copy) { 
        std::cout << "Foo::cctor()" << std::endl; 
    } 
    Foo& operator=(Foo const& copy) { 
        std::cout << "foo::assign()" << std::endl; 
        return *this; 
    } 
};

int main(int, const char**) { 
    Foo f; 
    Foo b(f); 
    Foo x = b;
    return 0; 
}

The result from running this should be:

Foo::ctor()
Foo::cctor()
Foo::cctor()

If you run it and get an foo::assign(), throw your compiler away and get one that works (oh, and let us know what compiler it is that's so badly broken)!

Answer 3

They differ if a class has a constructor marked 'explicit'. Then, one of these does not work.

Otherwise, no difference.