1. In an ecommerce system, you want to hide sensitive user details like passwords. Which OOP principle helps achieve this?

2. What is the output of this program?

#include

int main() {

int x = 0;

while (x < 3) { x++; } std::cout << x; return 0; }

3. What will be the output of following program?

#include
void main()
{
int colour = 2;
switch (colour) {
case 0:
printf("Black");
case 1:
printf("Red");
case 2:
printf("Aqua");
case 3:
printf("Green");
default:
printf("Other");
}
}

4. A bank application requires different types of accounts such as SavingsAccount and CurrentAccount. What OOP concept is used to achieve this?

5. What is the key difference between LinkedList and ArrayList?

6. What will be the output of the following code?
java
class Test {
public static void main(String[] args) {
String s1 = "abc";
String s2 = new String("abc");
System.out.println(s1 == s2);
}
}

7. What is the purpose of alignas in C++?

8. Which of these is a non-static member initialization in C++11?

9. A car rental system has a Vehicle class with subclasses like Car and Bike. If Vehicle cannot be instantiated, which feature is being used?

10. Which of the following functions cannot be used with FILE* in C?

11. What will happen if you free a pointer twice?

12. Which of the following is true about volatile keyword in Java?

13. What is the purpose of typeid in C++?

14. What happens when this code is executed?

#include

void func() { throw std::runtime_error("Error"); }

int main() {

try { func(); }

catch (const std::exception& e) { std::cout << e.what(); } return 0; }

15. What will happen if you access memory beyond the array size in C?

16. What will be the output of this code?

#include

int main() {

int x = 5;

int y = x++ + ++x;

printf("%d", y);

return 0;

}

17. What would be output following C program?

#include
int main()
{
char* str = "IncludeHelp";
printf("%c\n", *&*str);
return 0;
}

18. In a banking application, if a Withdrawal operation exceeds the balance, a BalanceInsufficientException is thrown. What is this an example of?

19. Which C++ feature allows iteration over a collection without exposing its implementation?

20. What happens if you attempt to access an out-of-bounds element in a std::vector using operator[]?