comScore Interview Questions, Process, and Tips

A friend function is a non-member function that has access to the private and protected members of a class.

• Declared inside the class but defined outside the class scope

• Can access private and protected members of the class

• Not a member of the class but has access to its private members

• Used to allow external functions to access and modify private data of a class

• Can be declared as a friend in another class

atoi function converts a string to an integer in C.

• The function takes a string as input and returns an integer.

• Leading white spaces are ignored.

• If the string contains non-numeric characters, the function stops conversion and returns the converted value.

• The function returns 0 if the input string is not a valid integer.

• Example: atoi('123') returns 123.

A program to print star pattern

• Use nested loops to print the pattern

• The outer loop controls the number of rows

• The inner loop controls the number of stars to be printed in each row

• Use print() or println() function to print the stars

Run time polymorphism is the ability of a program to determine the object type at runtime and call the appropriate method.

• It is achieved through virtual functions and dynamic binding.

• Allows for more flexible and extensible code.

• Example: a base class Animal with virtual function makeSound() and derived classes Dog and Cat that override makeSound().

• At runtime, if an Animal pointer points to a Dog object, calling makeSoun

Right outer join is a type of join operation that returns all the rows from the right table and the matching rows from the left table.

• Right outer join is denoted by the RIGHT JOIN keyword in SQL.

• It is used to combine rows from two tables based on a related column.

• In the result set, unmatched rows from the right table will have NULL values for the columns of the left table.

• A real-world scenario for using a right outer j...read more

Refrential integrity ensures that relationships between tables in a database remain consistent.

• It is a database concept that ensures that foreign key values in one table match the primary key values in another table.

• It prevents orphaned records in a database.

• It maintains data consistency and accuracy.

• For example, if a customer record is deleted, all related orders for that customer should also be deleted.

• It is enforced...read more

Primary key uniquely identifies a record in a table, while Unique key ensures uniqueness of a column.

• Primary key can't have null values, Unique key can have one null value

• A table can have only one Primary key, but multiple Unique keys

• Primary key is automatically indexed, Unique key is not necessarily indexed

Triggers are database objects that are automatically executed in response to certain events.

• Triggers can be used to enforce business rules, audit changes, or replicate data.

• There are two types of triggers: DML triggers and DDL triggers.

• DML triggers are fired in response to DML statements (INSERT, UPDATE, DELETE).

• DDL triggers are fired in response to DDL statements (CREATE, ALTER, DROP).

Swapping two character variables without using third

• Use XOR operator to swap two variables without using third variable

• Assign the XOR of both variables to the first variable

• Assign the XOR of the first variable and second variable to the second variable