// # Sample
// Diagnostics
//
// # Description
// The `Microsoft.Quantum.Diagnostics` namespace provides functionality for inspecting and
// diagnosing program state. This is useful when debugging or diagnosing behavior.
// Q# provides a number of features designed to enable testing and debugging Q# programs,
// primarily in the form of assertions and messaging classical state to the user.

import Std.Diagnostics.DumpMachine, Std.Diagnostics.Fact;

operation Main() : Unit {
    // `Message` emits a debug log.
    Message("Program is starting.");

    use qs = Qubit[2];
    CNOT(qs[0], qs[1]);
    H(qs[0]);

    // We may now want to see the state of `qs` after applying some gates to them.
    // `DumpMachine` displays the quantum state of the qubits.
    DumpMachine();

    // To ensure qubits are in the ground or |0⟩ state before being released, we can reset them.
    ResetAll(qs);

    // `Fact` checks whether a classical condition is true, and throws an
    // error with the specified message if not.
    Fact(1 == 1, "1 should always be equal to 1");
}
