c++ - Set a value of a class from another class -

i'm trying set value of member of class class using snippet. here sample of code i'm trying make work

class { private: int a; public: a() {     = 0; } a(int val) {     = val; } int geta() {     return  a; }  void seta() {     = 290; } };   class b {  b(){};   void setb() {      a;      a.seta(); }  };   int main(){ a; b b; b.setb(); cout << b.geta();  } 

how can make code pint out 290.i prints out 0

in setb a variable temporary destroyed when function returns.