Alamo XS Real Interview Questions and Answers

Map and unordered map are implemented as associative containers in C++ STL library.

• Map is implemented as a balanced binary search tree while unordered map is implemented as a hash table.

• Map stores elements in a sorted order while unordered map does not guarantee any specific order.

• Map has a logarithmic time complexity for insertion, deletion, and search operations while unordered map has an average constant time complexity for these operations.

• Map allows only unique keys whil...read more

Debugging C++ program with segmentation fault using GDB

• Compile the program with -g flag to include debugging symbols

• Run the program with GDB and set breakpoints at suspected functions

• Use 'run' command to execute the program within GDB

• Use 'backtrace' command to see the call stack when the segmentation fault occurs

• Use 'print' command to inspect variables and memory addresses

• Use 'core dump' command to generate a core dump file for post-mortem analysis

To grep a value from a file with key=value format, use awk command with delimiter as '=' and search for the key.

• Use awk command with delimiter as '=' to split the line into key and value

• Search for the key in the key column and print the corresponding value column

• Example: awk -F'=' '/key/ {print $2}' file.txt

Use C++ map or unordered_map to store key value pairs with same key

• C++ map and unordered_map are associative containers that store elements in key value pairs

• If the key is same for some entries, map will store only one entry while unordered_map can store multiple entries

• Example: map myMap; myMap["key1"] = 1; myMap["key2"] = 2; myMap["key1"] = 3; // myMap["key1"] will be 3

• Example: unordered_map myUnorderedMap; myUnorderedMap["key1"] = 1; myUnorderedMap["key2"] = 2; myUnordered...read more

Virtual functions are functions that can be overridden in derived classes. Vtables are tables of function pointers used for dynamic dispatch.

• Virtual functions allow for polymorphism and dynamic binding

• Vtables are used to implement virtual functions

• Method overriding is when a derived class provides its own implementation of a virtual function

• Virtual functions are declared using the virtual keyword

• Example: class Animal { virtual void makeSound() { cout << 'Animal sound'; } }; c...read more

Explanation of directives, dependency injection, promise and observables, routing, interceptor, and communication between components.

• Directives are markers on a DOM element that tell AngularJS to attach a specified behavior to that element.

• Dependency Injection is a design pattern that allows a class to be injected with its dependencies rather than creating them itself.

• Promises are objects that represent the eventual completion or failure of an asynchronous operation and its r...read more

A singleton class is a class that can only have one instance created throughout the lifetime of an application.

• Create a private constructor to prevent external instantiation.

• Create a private static instance of the class.

• Create a public static method to access the instance.

• Ensure thread safety by using synchronized keyword or static initializer.

• Example: public class Singleton { private static Singleton instance = null; private Singleton() {} public static synchronized Singleto...read more

A singleton class is a class that can only have one instance created at a time.

• Singleton classes are often used in situations where only one instance of a class is needed, such as for managing a database connection or a configuration file.

• The singleton pattern is implemented by making the constructor of the class private and providing a static method that returns the single instance of the class.

• Singleton classes can be thread-safe by using synchronization or lazy initializat...read more