C++ Based Questions

In C++, destructors are special member functions used to clean up objects. They are defined without parameters and cannot be overloaded, meaning they always take zero arguments.

A pure virtual function is declared in a base class with no implementation, typically using the syntax = 0. It forces derived classes to provide their own implementation.

Passing by reference creates a direct link between the formal parameter and the actual argument. Any changes made to the formal parameter inside the function directly affect the original variable.

In C-style strings, the null terminator character, represented as '\0', marks the end of the string. The option provided uses a hyphen, which is a common OCR or transcription error for the backslash character.

A constructor that takes no arguments is known as the default constructor. If no constructor is defined, the compiler provides one automatically.

A friend function is a non-member function that is explicitly granted access to the private and protected members of a class. This is useful for operator overloading and specific utility functions.

The sizeof operator returns the size of a type in bytes. On most modern systems, a float occupies 4 bytes of memory.

The tilde (~) operator is the bitwise NOT operator in C++. The other options are logical operators (!) or comparison operators (==, !=).

C++ arrays are zero-indexed. Therefore, the first element is at index 0, the second at index 1, and the third element is at index 2.

Function templates are defined using the 'template' keyword followed by the template parameter list in angle brackets.

In C++, an array is a collection of elements of the same data type stored in contiguous memory locations. It cannot store mixed data types.

A pointer is a variable that holds the memory address of another variable, rather than holding a direct data value like an integer or float.

The loop condition is I <= a. Since a is initialized to 0 and I is initialized to 1, the condition 1 <= 0 is false from the start. Therefore, the loop body never executes.

The function x uses pass-by-reference for b. Inside x: a becomes 4+10=14, then a becomes 14-10=4, then b becomes 10-4=6. The original a remains 4, and b is updated to 6.

A constructor is a special member function that must have the exact same name as the class it belongs to.

The setw() manipulator (set width) is used to set the field width for the next output operation.

A union is a special data type that allows storing different data types in the same memory location, where only one member can contain a value at any given time.

In C++, the result of the modulo operator (%) with negative numbers follows the sign of the dividend. -16 % -3 results in -1 because -16 = (-3 * 5) + (-1).

In C++, multiple inheritance is specified by listing the base classes separated by commas after the colon, with the access specifier for each.

Encapsulation is the object-oriented programming concept that binds together the data and the functions that manipulate that data into a single unit, usually a class.

Yes, class objects can be passed to functions either by value, by reference, or by pointer, just like primitive data types.

a++ uses the current value (10) then increments a to 11. ++a increments a to 12 then uses the value (12). So b = 10 * 12 = 120. After execution, a is 12.

Function overloading occurs when multiple functions have the same name but different parameter lists (different number or types of arguments). Option A changes the number of arguments, which is a valid overload.

The default case in a switch statement is optional. It is used to handle values that do not match any of the specified case labels, but it is not syntactically required.

When a file is opened in ios::out mode, it is opened for writing. By default, this mode also includes ios::trunc, which clears the file contents if it already exists.