Which operating system introduced new features such as virtual memory and
the ability to drag and drop files in 1991?
a. dos
b. windows
c. macintosh
d. unix

What is the output of the following program? #include using namespace std; class bclass { public: void print() const; bclass(int a = 0, int b = 0); //postcondition: x = a; y = b; private: int x; int y; }; class dclass: public bclass { public: void print() const; dclass(int a = 0, int b = 0, int c = 0); //postcondition: x = a; y = b; z = c; private: int z; }; int main() { bclass bobject(2, 3); dclass dobject(3, 5, 8); bobject. print(); cout < < endl; dobject. print(); cout < < endl; return 0 ; } void bclass: : print() const { cout < < x < < " " < < y < < endl; } bclass: : bclass(int a, int b) { x = a; y = b; } void dclass: : print() const { bclass: print(); cout < < " " < < z < < endl; } dclass: : dclass(int a, int b, int c) : bclass(a, b) { z = c; }