Checking the identity of the state of qubits using the CSWAP operator

Currently, quantum computing and quantum computers are beginning to actively penetrate into an increasing number of areas and begin to go beyond the scope of only scientific theoretical activity. Therefore, now it is very timely to study in detail the elements of quantum programming, which, quite possibly, in the near future, can be actively used, including in industrial automation. In this work, we will get acquainted with such an element of quantum programming as CSWAP, analyze the logic of its operation on the classical scheme for checking two qubits for equality, and also build and test a circuit that allows checking for equality of two qubits that are in a state of superposition.