c++ - In the following code how can I initialize a class member without using dummy values? -

c++ - In the following code how can I initialize a class member without using dummy values? -

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what weird colon-member (“ : ”) syntax in constructor? 11 answers

// illustration program

#include <iostream> #include <vector> #include <array> class a{ public: a(int tempy){ y = tempy; } int y = 0; }; class b{ public: b(a tempz){ z = tempz.y; } z; }; int main() { int x = 1; obja(x); b objb(obja); std::cout << "y = " << objb.z << "!\n"; }

build at: http://cpp.sh/3yj2

there error in class b because haven't passed constructor parameter fellow member z. don't want initialize dummy value, there way utilize constructor parameters build fellow member z, , how tell z utilize b's constructor parameters?

if i'm missing fundamental aspect of c++ please allow me know i'm starting out.

you can utilize initializer lists this

class b{ public: b(a tempz) : z(tempz) { } z; };

this way z initialized new instance of created re-create constructor.

c++