c++ telescoping constructor is NOT supported until c++11

Telescoping constructor: see Effective Java 2nd Edition Item 2

If you want to use telescoping constructor but your compiler does not support c++11 standards, you can use default parameter instead, see code snippets 'main.cpp', 'Box.h', 'Box.cpp'.

If your compiler supports c++11 standards, the syntax of telescoping is shown in code snippet 'Box2.h' and 'Box2.cpp', and you might need to use '-std=c++11' parameter when you are compiling your source code.

For now, I'd like to use default parameter.

main.cpp

 #include "Box.h"

 int main()

 {

     Box box;

     box.print();

     Box box2();

     box2.print();

     Box box3(, 'A');

     box3.print();

     Box box4(, 'A', 1.88);

     box4.print();

     return ;

 }

Box.h

 #ifndef BOX_H

 #define BOX_H

 class Box

 {

     public:

         Box(const int &_a = , const char &_b = 'M', const double &_c = 0.99);

         ~Box();

         void print();

     private:

         int a;

         char b;

         double c;

 };

 #endif // BOX_H

Box.cpp

 #include "Box.h"

 #include <iostream>

 using namespace std;

 Box::Box(const int &_a, const char &_b, const double &_c)

 : a(_a), b(_b), c(_c)

 {

 }

 Box::~Box()

 {

 }

 void Box::print() {

     cout << "a = " << a << ",b = " << b << ",c = " << c << endl;

 }

Box2.h

 #ifndef BOX_H

 #define BOX_H

 class Box

 {

     public:

         Box(const int &_a, const char &_b, const double &_c);

         Box(const int &_a, const char &_b);

         Box(const int &_a);

         Box();

         ~Box();

         void print();

     private:

         int a;

         char b;

         double c;

 };

 #endif // BOX_H

Box2.cpp

 #include "Box.h"

 #include <iostream>

 using namespace std;

 Box::Box(const int &_a, const char &_b, const double &_c)

 : a(_a), b(_b), c(_c)

 {

 }

 Box::Box(const int &_a, const char &_b)

 : Box(_a, _b, 0.99)

 {

 }

 Box::Box(const int &_a)

 : Box(_a, 'M')

 {

 }

 Box::Box()

 : Box()

 {

 }

 Box::~Box()

 {

 }

 void Box::print() {

     cout << "a = " << a << ",b = " << b << ",c = " << c << endl;

 }

巴特西

c++ telescoping constructor is NOT supported until c++11

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