banner
cells

cells

为美好的世界献上 bug

quiz

Q027#

Answer

click to see answer B

Q029#

Answer

click to see answer 121

Explain

Even though A::foo() is a virtual function, it is not considered virtual during construction and destruction.

Before constructing B, A should be constructed, and during the construction of A, B is not yet constructed, so it should not be used, the foo() called in A::A() naturally calls A::foo().

When the object b is destroyed, the same problem arises because B's destructor is called first, followed by A's destructor, and after the object b is destroyed, B::foo() should not be used.

Q114#

Answer

click to see answer AAABBAAB

Explain

C *const p1 const modifies the p1 pointer, so when foo is called on the member variable p1 of object s, the non-const version of foo will be used. C const *p2 const modifies the *p (C object), so when foo is called on the member variable p2 of object s, the const version of foo will be used.

r is a constant reference to object s, and const changes the behavior of member v because std::vector overloads operator[] and the version called by a constant object returns a constant reference, so the returned value is also a constant reference, so calling foo will use the const version.

Q360#

Answer

click to see answer 0110001

Explain

const int * is a pointer to a constant integer, which means a constant pointer, although the content pointed to by the pointer is constant, the pointer itself is not constant, so the result is false.

int *const is a constant pointer, the pointer itself is constant, so the result is true.

const int[1] is an array containing constant integers, the elements of the array are constants, so the result is true.

const int ** is a pointer to a pointer to a constant pointer ( (const int *) *ptr ), the pointer itself is not constant, so the result is false.

int *const * is a pointer to a constant pointer ( (int *const) *ptr ), the pointer itself is not constant, so the result is false.

const int (*)[1] is a pointer to an array of constant integers, the pointer itself is not constant, so the result is false.

const int *[1] is an array of pointers to constant integers ( const int *ptr[1] ), the elements of the array are constant pointers, so the result is false.

const int[1][1] is a two-dimensional array, the elements of which are constants, so the result is true.

Loading...
Ownership of this page data is guaranteed by blockchain and smart contracts to the creator alone.