Stage 1 · Code

Variables, Types & Control Flow

if and switch

Write conditional logic in Go with concise if statements, initialization clauses, and expressive switch expressions.

7 min readProgramming Foundations (Go)Code

Basic if

An if statement in Go runs a block of code only when a boolean expression is true. The condition does not need parentheses, but the body must be wrapped in curly braces — even for a single line.

Gothe-simplest-if.go

20 linesLn 1, Col 1Go

Go's syntax enforces braces and forbids parentheses around the condition. Both rules are checked by `gofmt` and the compiler. No style debates needed.

Only boolean conditions allowed

Go does not treat zero, empty string, or nil as false. You must write an explicit comparison: if len(s) == 0, if n != 0, if ptr != nil. This removes an entire class of subtle bugs found in C or JavaScript.

if / else if / else Chains

When you have more than two outcomes, chain conditions with else if. Only the first true branch runs; the rest are skipped. A final else is a catch-all for everything the earlier conditions missed.

Gograde-classification.go

24 linesLn 1, Col 1Go

Each `else if` is only evaluated when all previous conditions were false. Returning early from each branch instead of nesting makes the control flow easy to trace.

Avoid deep nesting — return early

When the happy path is one condition among many error cases, check errors first and return early. This keeps the main logic at the outermost indent level and makes functions easier to read from top to bottom.

Initialization Clause

Go's if statement supports an optional initialization clause before the condition. It declares a variable that exists only inside the if block (and any else block). This scopes temporary values exactly where they are needed.

Goif-with-initialization.go

25 linesLn 1, Col 1Go

The `n, err := strconv.Atoi(input)` initialization runs before the condition is tested. Both `n` and `err` are scoped to the `if` statement — they do not pollute the outer function scope.

switch Statements

A switch statement is a cleaner alternative to a long else if chain. Each case is tested in order; the first match runs and the switch ends. Unlike C or Java, Go does not fall through to the next case by default.

Goswitch-on-a-value.go

21 linesLn 1, Col 1Go

Listing multiple values in one case with a comma is much cleaner than `else if day == "Saturday" || day == "Sunday"`. The `default` case is optional and catches anything not matched above.

Goswitch-without-an-expression-(condition-switch).go

25 linesLn 1, Col 1Go

A `switch` without a value behaves like an `if / else if` chain, but each `case` can be any boolean condition. This is often more readable than a long `else if` ladder.

fallthrough and Multi-Case

When you explicitly need the next case to run after a matching case, use the fallthrough keyword. It transfers control unconditionally to the start of the next case — not its condition, but its body.

Gofallthrough.go

21 linesLn 1, Col 1Go

`fallthrough` is rarely needed and can make code hard to follow. Prefer listing multiple values in a single case (`case 1, 2, 3:`) or restructuring the logic.

switch with an initialization clause

Just like if, switch also accepts an initialization clause: switch n := computeValue(); { case n > 0: ... }. This scopes the temporary variable n to the switch block only.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.

Stage 1 · Code

Variables, Types & Control Flow

if and switch

Write conditional logic in Go with concise if statements, initialization clauses, and expressive switch expressions.

7 min readProgramming Foundations (Go)Code

Basic if

An if statement in Go runs a block of code only when a boolean expression is true. The condition does not need parentheses, but the body must be wrapped in curly braces — even for a single line.

Gothe-simplest-if.go

20 linesLn 1, Col 1Go

Go's syntax enforces braces and forbids parentheses around the condition. Both rules are checked by `gofmt` and the compiler. No style debates needed.

Only boolean conditions allowed

if / else if / else Chains

Gograde-classification.go

24 linesLn 1, Col 1Go

Each `else if` is only evaluated when all previous conditions were false. Returning early from each branch instead of nesting makes the control flow easy to trace.

Avoid deep nesting — return early

Initialization Clause

Goif-with-initialization.go

25 linesLn 1, Col 1Go

The `n, err := strconv.Atoi(input)` initialization runs before the condition is tested. Both `n` and `err` are scoped to the `if` statement — they do not pollute the outer function scope.

switch Statements

Goswitch-on-a-value.go

21 linesLn 1, Col 1Go

Listing multiple values in one case with a comma is much cleaner than `else if day == "Saturday" || day == "Sunday"`. The `default` case is optional and catches anything not matched above.

Goswitch-without-an-expression-(condition-switch).go

25 linesLn 1, Col 1Go

A `switch` without a value behaves like an `if / else if` chain, but each `case` can be any boolean condition. This is often more readable than a long `else if` ladder.

fallthrough and Multi-Case

Gofallthrough.go

21 linesLn 1, Col 1Go

`fallthrough` is rarely needed and can make code hard to follow. Prefer listing multiple values in a single case (`case 1, 2, 3:`) or restructuring the logic.

switch with an initialization clause

Just like if, switch also accepts an initialization clause: switch n := computeValue(); { case n > 0: ... }. This scopes the temporary variable n to the switch block only.

Mark this lesson complete to store local progress and unlock a cleaner resume path the next time you visit.