Self-test 2:
C++ const-ness

Which is const class member function?

class A
{
  private:
    const int a(int); // [A]
    int b(const int); // [B]
    int c(int) const; // [C]
    ......
};

Solution

Which of the following definitions of a does not allow later assignment like below:

                   *a = 3;

(There can be multiple answers.)

    int b = 100;
    const int* a = &b;           // [1]
    int const* a = &b;           // [2]
    int* const a = &b;           // [3]
    const int* const a = &b;     // [4]

Solution

[1][2][4]

Which of the following definitions of pointer a does not allow later its re-direction to point to another object? (There can be multiple answers.)

    int b = 100;
    const int* a = &b;           // [1]
    int const* a = &b;           // [2]
    int* const a = &b;           // [3]
    const int* const a = &b;     // [4]

Solution

[3] [4]

When a function is declared as "const char* GetString(void);" which of the following statements will compile with no warnings nor errors?
1. char* str = GetString( );
2. const char* str = GetString( );
3. char* const str = GetString( );
4. const char* const str = GetString( );
Solution

B,D
What is the difference between the following two declarations of the function GetInt? Or are they are same in effect?
```
    const int GetInt(void)
    int GetInt(void)
```
Solution

Their effects are the same since the value returned is an copied value, so it doesn't really matter if it is a const or not.
Which expression(s) below is(are) legal?
1. const A_class* c = new A_class(); A_class* e = c;
2. A_class* const c = new A_class(); A_class* b = c;
Solution

B

Is the following, point out the illegal statements.

    class Stack
    {
      public:
	void push(int elem);
	int pop(void);
	int getCount(void) const;
      private:
	int num;
	int data[100];
    };

    int Stack::getCount(void) const
    {
	++num;   // [1]
	pop();   // [2]
	return num;
    }

Solution

[1][2]

Self-test 2: C++ const-ness

Self-test 2:
C++ const-ness