microsoft/qdk

// OpenQASM Hello World sample
//
// This is one of the simplest OpenQASM programs that contains quantum part.
// It uses one qubit, resets it and and immediately measures it.
// Since the qubit is in |0〉 state after reset
// such measurement will always yield `Zero`.

// OpenQASM version identifier.
OPENQASM 3;

// Declares use of a single qubit and names it `q`.
// All qubits must be declared in a global scope.
qubit q;

// Qubits are initially in an undefined state.
// Reset is used here to initialize qubit to a |0〉 state.
reset q;

// Measures qubit and stores the result in a classical bit.
// The qubit is in |0〉 state after reset, so the `b` will be 0.
bit b = measure q;

// Note, that the content of all classical variables
// are reported to the user at the end of the program
// unless explicit output declarations exist.