Go switch Statement

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Go switch Statement

The switch statement in Go is a powerful control flow construct used to select one of many code blocks for execution. It provides a cleaner and more readable alternative to writing multiple if...else if conditions.

Unlike languages such as C, C++, or Java, Go’s switch executes only the first matching case by default—meaning you do not need a break statement.

Basic Syntax of switch

switch expression { case value1: // code block case value2: // code block case value3: // code block default: // code block (optional) }

How the switch Statement Works

• The expression is evaluated once.
• Its result is compared against each case value.
• When a match is found, the corresponding block of code is executed.
• Only the first matching case runs.
• The default block executes if no match is found (optional but recommended).

Example 1: Displaying Day Name

package main import "fmt" func main() { dayNumber := 5 switch dayNumber { case 1: fmt.Println("Monday") case 2: fmt.Println("Tuesday") case 3: fmt.Println("Wednesday") case 4: fmt.Println("Thursday") case 5: fmt.Println("Friday") case 6: fmt.Println("Saturday") case 7: fmt.Println("Sunday") } }

Friday

Example 2: Using the default Case

The default case acts as a fallback when no other case matches.

package main import "fmt" func main() { score := 105 switch score { case 0, 1, 2, 3, 4: fmt.Println("Very Low Score") case 5, 6, 7, 8: fmt.Println("Average Score") case 9, 10: fmt.Println("Excellent Score") default: fmt.Println("Invalid score") } }

Invalid score

Key Features of Go switch

• No need for break statements (automatic termination after a match).
• Supports multiple values in a single case (e.g., case 1, 2, 3:).
• The default case is optional but improves robustness.
• Cleaner and more readable than long if...else if chains.

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Go Multi-Case switch

In Go, the switch statement becomes even more powerful when you assign multiple values to a single case. This feature allows you to group conditions and execute the same block of code for different matching values—making your code cleaner and more concise.

Syntax of Multi-Case switch

switch expression { case value1, value2: // executes if expression matches value1 OR value2 case value3, value4: // executes if expression matches value3 OR value4 default: // executes if no case matches }

How It Works

• The expression is evaluated once.
• Each case can contain multiple comma-separated values.
• If the expression matches any value within a case, that block is executed.
• Only the first matching case runs.
• The default block handles unmatched values.

Example: Categorizing Days of the Week

package main import "fmt" func main() { day := 6 switch day { case 1, 3, 5: fmt.Println("Weekday: Odd schedule") case 2, 4: fmt.Println("Weekday: Even schedule") case 6, 7: fmt.Println("Weekend: Time to relax") default: fmt.Println("Invalid day number") } }

Weekend: Time to relax

Example: Grouping User Roles

package main import "fmt" func main() { role := "editor" switch role { case "admin", "superuser": fmt.Println("Full system access granted") case "editor", "author": fmt.Println("Content editing permissions granted") case "viewer", "guest": fmt.Println("Read-only access") default: fmt.Println("Unknown role") } }

Content editing permissions granted

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