Learn QSHARP with Real Code Examples

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterBasic() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit {
        Message($"Counter: {count}");
        Message($"Theme: {(if isDark then "Dark" else "Light")}");
        }

        operation Increment() : Unit {
        set count += 1;
        UpdateUI();
        }

        operation ToggleTheme() : Unit {
        set isDark = not isDark;
        UpdateUI();
        }

        UpdateUI();
        Increment();
        ToggleTheme();
    }
}

Basic counter with theme toggle using Q# operations.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterWithDecrement() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit {
        Message($"Counter: {count}");
        Message($"Theme: {(if isDark then "Dark" else "Light")}");
        }

        operation Increment() : Unit { set count += 1; UpdateUI(); }
        operation Decrement() : Unit { set count -= 1; UpdateUI(); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(); }

        UpdateUI();
        Increment();
        Increment();
        Decrement();
        ToggleTheme();
    }
}

Adds a decrement operation.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterWithReset() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit { Message($"Counter: {count}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation Increment() : Unit { set count += 1; UpdateUI(); }
        operation Reset() : Unit { set count = 0; UpdateUI(); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(); }

        UpdateUI();
        Increment();
        Increment();
        Reset();
        ToggleTheme();
    }
}

Adds a reset operation to reset the counter.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterInlineToggle() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit { Message($"Counter: {count}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation IncrementAndToggle() : Unit { set count += 1; set isDark = not isDark; UpdateUI(); }

        UpdateUI();
        IncrementAndToggle();
    }
}

Toggles theme inline during increment or decrement.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterConditional() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit {
        Message($"Counter: {count}");
        Message($"Theme: {(if isDark then "Dark" else "Light")}");
        if (count == 3) { Message("Reached 3!"); }
        }

        operation Increment() : Unit { set count += 1; UpdateUI(); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(); }

        UpdateUI();
        Increment();
        Increment();
        Increment();
        ToggleTheme();
    }
}

Displays extra message when counter reaches 3.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterLoop() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit { Message($"Counter: {count}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation Increment() : Unit { set count += 1; UpdateUI(); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(); }

        for (i in 1..3) { Increment(); }
        ToggleTheme();
    }
}

Uses a for loop to increment counter multiple times.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterParam() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI(c: Int) : Unit { Message($"Counter: {c}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation Increment() : Unit { set count += 1; UpdateUI(count); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(count); }

        UpdateUI(count);
        Increment();
        ToggleTheme();
    }
}

Passes count as parameter to UpdateUI operation.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterCombined() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit { Message($"Counter: {count}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation IncrementAndToggle() : Unit { set count += 1; set isDark = not isDark; UpdateUI(); }

        UpdateUI();
        IncrementAndToggle();
        IncrementAndToggle();
    }
}

Combines increment and toggle in a single operation.

namespace QuantumExamples {
    open Microsoft.Quantum.Intrinsic;
    open Microsoft.Quantum.Canon;

    operation CounterLoopReset() : Unit {
        mutable count = 0;
        mutable isDark = false;

        operation UpdateUI() : Unit { Message($"Counter: {count}"); Message($"Theme: {(if isDark then "Dark" else "Light")}"); }
        operation Increment() : Unit { set count += 1; UpdateUI(); }
        operation Reset() : Unit { set count = 0; UpdateUI(); }
        operation ToggleTheme() : Unit { set isDark = not isDark; UpdateUI(); }

        for (i in 1..5) { Increment(); }
        Reset();
        ToggleTheme();
    }
}

Combines loop increments and reset operation.