I have class called Bar, and in this class Bar there is an object of type Foo (a class). Class Bar takes 3 parameters, x, y and z. Foo takes 2 parameters, y and z.
currently I'm doing this:
class Bar { public: Bar(int x, int y, int z) { foo = new Foo(y, z); do something with x; } private: Foo * foo; }; I remember seeing in a book another way to do this using a colon but I don't remember how exactly.
What is the standard or usual way of doing something like this?
Use an initializer list and avoid dynamic allocation:
class Bar { public: Bar(int x, int y, int z) : foo(y, z) {} private: Foo foo; }; 
class Bar { public: Bar(int x, int y, int z) : foo(y, z) { do something with x; } private: Foo foo; }; your perplexing line should be
... Bar(int x, int y, int z) : foo(new Foo(y,z)) { ... private: Foo* foo; ... i see other answers dont use pointer. But correct one should be this.
Foo then used a pointer initialization because we dont know the internal structure of Foo. Maybe there are link lists and the user want to do foo = foo->next; in somewhere.Besides it is good to learn preferring non-pointer objects is a common practice.