19 различных способов инициализировать int в C++:

int i1;                 //undefined value
int i2 = 42;            //note: inits with 42
int i3(42);             //inits with 42
int i4 = int(42);       //inits with 42
int i5{42};             //inits with 42
int i6 = {42};          //inits with 42
int i7{};               //inits with 0
int i8 = {};            //inits with 0
auto i9 = 42;           //inits with 42
auto i10{42};           //C++11: std::initializer_list<int>, C++14: int
auto i11 = {42};        //inits std::initializer_list<int> with 42
auto i12 = int{42};     //inits int with 42
int i13();              //declares a function
int i14(7, 9);          //compile-time error
int i15 = (7, 9);       //OK, inits int with 9 (comma operator)
int i16 = int(7, 9);    //compile-time error
int i17(7, 9);          //compile-time error
auto i18 = (7, 9);      //OK, inits int with 9 (comma operator)
auto i19 = int(7, 9);   //compile-time error

И это только начало:
https://youtu.be/h-zy1hBqT74

Спасибо, не надо.