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Preference when initializing variables in C ++

Run in C ++ and notice that you can initialize a variable in two ways.

int example_var = 3;  // with the assignment operator '='

or

int example_var(3);  // enclosing the value with parentheses

Is there a reason to use one over the other?

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4 answers

The first form goes back to C time, and the second goes back to C ++. The reason for the addition is that in some contexts (in particular, initializer lists in constructors) the first form is not allowed.

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std::string s = std::string();  // ok declares a variable
std::string s( std::string() ); // declares a function: std::string s( std::string(*)() )

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std::string s{std::string{}};

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They compile to the same thing. However, both are a form of initialization variable, not assignment, which matters a little in C and a lot in C ++, since completely different functions are called (constructor v. Assign).

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