C++ and Python Quiz

Find the Output
#include using namespace std; int main() { int* a, b; cout << typeid(a).name() << endl; cout << typeid(b).name() << endl; return 0; }

• a is an int*, b is an int

• Both a and b are int*

• Both a and b are int

• Compilation error

Answer explanation

a is declared as a pointer to int, but b is just a plain int. Only a gets the * (pointer). b is just a regular int. Pi denotes type Pointer(Int) .i denotes Integer.

Find the output #include using namespace std; int main() { int p; bool a = true; bool b = false; int x = 10; int y = 5; p = ((x | y) + (a + b)); cout << p; return 0; }

• 12

• 0

• 2

• 16

Answer explanation

| means bitwise OR operation so x | y (0101 | 1010) will be evaluated to 1111 which is integer 15 and as a is true and b is false so a+b(1 + 0) = 1. So final value of expression in line #10 will be 15 + 1 = 16.

Find the Output :

    #include <iostream>

    using namespace std;

    int main()

    {

        int a = 5;

        cout << sizeof(++a) <<endl;

        cout << a;

        return 0;

    }

• 2 5

• 4 5

• 4 6

• 2 6

Answer explanation

In this C++ program, a variable a is initialized with the value 5. The line sizeof(++a) might seem like it would increment a, but it does not. This is because the sizeof operator in C++ is evaluated at compile time and does not actually evaluate the expression inside it. Instead, it only checks the type of the expression, which in this case is int. Therefore, sizeof(++a) simply returns the size of an int, which is typically 4 bytes on most systems.

As a result, the value of a remains unchanged. When the program prints sizeof(++a), it outputs 4, and when it prints a, it outputs 5. This demonstrates that sizeof does not cause side effects or execute any operations on the variables used within it.

Which of the following symbol is used to declare the preprocessor directives in C++?

• $

• ^

• #

• *

How structures and classes in C++ differ?

• Structures by default hide every member whereas classes do not

• In Structures, members are public by default whereas, in Classes, they are private by default

• Structures cannot have private members whereas classes can have

• In Structures, members are private by default whereas, in Classes, they are public by default

What will be the output of the following C++ code?

#include using namespace std; int main () { int a, b, c; a = 2; b = 7; c = (a > b) ? a : b; cout << c; return 0; }

• 12

• 14

• 6

• 7

Answer explanation

We are using the ternary operator to evaluate this expression. It will return first option, if first condition is true otherwise it will return second

Find the output #include using namespace std; int main () { int array[] = {0, 2, 4, 6, 7, 5, 3}; int n, result = 0; for (n = 0; n < 7; n++) { result += array[n]; } cout << result; return 0; }

• 21

• 27

• 26

• 25

Answer explanation

This C++ program calculates the sum of elements in an integer array. The array array[] is initialized with the values {0, 2, 4, 6, 7, 5, 3}. A variable result is used to accumulate the sum and is initialized to 0. The for loop runs from n = 0 to n < 7, meaning it iterates through all 7 elements of the array. In each iteration, the current array element array[n] is added to result. After the loop completes, result holds the total sum of the array elements. Finally, the program prints the sum, which is 27, as the sum of all elements 0 + 2 + 4 + 6 + 7 + 5 + 3 = 27.

Identify the incorrect option.

• enumerators are Named constants

• enumerators are user-defined types

• enumerators are same as macros

• enumerator values start from 0 by default

Answer explanation

enumerators are not the same as macros. Although both can represent constant values, they are conceptually and technically different. Enumerators are part of the enum keyword in C++, which defines a set of named integer constants within a user-defined type.

What will be the output of the following C++ code? #include using namespace std; enum test { A = 32, B, C }; int main() { cout << A << B<< C; return 0; }

• 323334

• 323232

• 323130

• 323134

Answer explanation

In C++, when an enumerator is given a specific value, the following enumerators (if not assigned manually) automatically receive incremented values. Therefore, B becomes 33 and C becomes 34. In the main() function, the program uses cout to print the values of A, B, and C one after the other. Since no spaces or formatting are used between them, the output appears as 323334.

What does the following statement mean? void a;

• variable a is of type void

• a is an object of type void

• declares a variable with value a

• flags an error

Answer explanation

In C++, the void type is a special type that means "no type" or "no value." It is typically used as a return type for functions that do not return anything.