This C++ Online Test
Separates Good From Bad Hires

Implement the unique_names method. When passed two vectors of names, it will return a vector containing the names that appear in either or both vectors. The returned vector should have no duplicates.

For example, calling unique_names(std::vector<std::string>{"Ava", "Emma", "Olivia"}, std::vector<std::string>{"Olivia", "Sophia", "Emma"}) should return a vector containing Ava, Emma, Olivia, and Sophia in any order.

Implement the function findRoots to find the roots of the quadratic equation: ax² + bx + c = 0. If the equation has only one solution, the function should return that solution as both elements of the pair. The equation will always have at least one solution.

The roots of the quadratic equation can be found with the following formula:

For example, the roots of the equation 2x² + 10x + 8 = 0 are -1 and -4.

User interface contains two types of user input controls: TextInput, which accepts all characters and NumericInput, which accepts only digits.

Implement the following methods:

• add on class TextInput - adds the given character to the current value
• getValue on class TextInput - returns the current value
• add on class NumericInput - overrides the base class method so that each non-numeric character is ignored

For example, the following code should output "10":

TextInput* input = new NumericInput();
input->add('1');
input->add('a');
input->add('0');
std::cout << input->getValue();

As part of a data processing pipeline, complete the implementation of the makePipeline method:

• The method should accept a vector of functions, and it should return a new function that accepts one parameter arg.
• The returned function should call the first function in the makePipeline with the parameter arg, and call the second function with the result of the first function.
• The returned function should continue calling each function in the makePipeline in order, following the same pattern, and return the value from the last function.

For example,

std::vector<std::function<int (int)>> functions;
functions.push_back([] (int x) -> int { return x * 3; });
functions.push_back([] (int x) -> int { return x + 1; });
functions.push_back([] (int x) -> int { return x / 2; });
std::function<int (int)> func = makePipeline(functions);

calling the func(3) should return 5.

Multiple choice test has several multiple choice questions. Each question can have only one correct answer. Additionally, timed multiple choice test can specify the time allowed for solving each question in the test.

The code below satisfies this specification, but the customer complained that the memory usage of the program constantly increases. Fix this problem.