Conditionals in C#

Control flow with if/else, switch statements, switch expressions (C# 8+), ternary operator, pattern matching in conditions, and guard clauses.

if, else if, else

An `if` block runs only when its condition is `true`.

Chain multiple conditions with `else if`. The `else` block runs if none of the conditions match.

An `if` inside another `if` — useful for checking multiple related conditions.

Unlike JavaScript, C# does not have truthy/falsy. Every `if` condition must be a `bool` expression.

Common patterns for checking empty, null, or zero values in C#.

`condition ? valueIfTrue : valueIfFalse` — a compact one-line conditional expression.

Use ternary to provide fallback values for null — though `??` is cleaner for null specifically.

Ternaries can be nested but become hard to read quickly. Prefer `if/else` for more than two outcomes.

Match a value against `case` labels. Each `case` needs a `break` to prevent fall-through.

Stack multiple `case` labels to share the same block — the only allowed form of fall-through in C#.

C# `switch` works on strings — the comparison is case-sensitive.

C# 8+ switch expressions use `=>` arrows, return a value, require no `break`, and must be exhaustive.

Use `,` to match multiple values in a single arm.

Add `when` to a case arm to apply an extra condition.

Return early at the top of a method when preconditions fail — avoids deep nesting.

Use `continue` to skip the rest of a loop iteration early — the loop equivalent of a guard clause.

Follow these patterns for clean, idiomatic C# conditional code.