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Swift If and Else

Select a notice while keeping invalid counts separate from a valid empty state.

How it works

An if condition is Bool. else if tests another condition only when the previous branch did not match, and else covers what remains. Nested branches are useful when the inner question depends on the outer one; otherwise a guard or small helper may be clearer.

Run this Swift example

Install the toolchain for your platform from Swift.org, then check swift --version. The reviewed portable baseline is Swift 6.4.2 in Swift 6 mode on Ubuntu 26.04 x86_64 through the PC’s existing WSL installation. These are real Linux executions, not claims of Windows-native or Apple-platform test results. Windows Swift has separate C++/SDK prerequisites in its official setup guide.

Save the complete source as if-else.swift in a new learning folder. On Linux/macOS compile with swiftc -swift-version 6 -parse-as-library if-else.swift -o lesson, then run ./lesson. On a configured Windows toolchain use an output such as lesson.exe and run .\lesson.exe. The parse-as-library option supports the explicit @main entry point used by these sources. Compile each ordinary lesson separately.

Bhylu has no Swift browser runner. The JavaScript/Python editors do not run these sources; Apache, PHP and MySQL are not required. Downloads are source text, never executable teaching endpoints.

Download the complete if-else.swift · Download all source files with hash checks

For the optional collection, save download-examples.mjs in a new folder and run node download-examples.mjs. A local preview uses node download-examples.mjs http://127.0.0.1:8000/examples/swift/. It refuses an existing bhylu-swift-examples folder and installs or executes no Swift automatically. Apple-only files remain separate Xcode learning examples, not a portable Swift package target.

Example

if-else.swift

func showNotice(places: Int) {
    if places < 0 {
        print("Invalid count")
    } else if places == 0 {
        print("Workshop full")
    } else {
        print("Booking available")
    }
    let badge = places > 0 ? "Open" : "Full"
    print(badge)
}

@main
struct Lesson {
    static func main() { showNotice(places: 3) }
}

Expected result

Booking available
Open

The ternary expression chooses a small text value without duplicating a larger branch. The separate negative case prevents an invalid count from being treated as a harmless full workshop.

Primary references: The Swift Programming Language and Apple framework documentation. Use the selected platform’s current requirements. Fictional workshop examples do not establish production safety or deployment approval.

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