Go switch

In Go, the switch statement is used to evaluate a variable or expression and choose a code block to execute based on its value. The syntax of the switch statement is as follows:

switch expression {
case value1:
    // code to be executed if expression equals value1
case value2:
    // code to be executed if expression equals value2
...
default:
    // code to be executed if expression doesn't equal any of the above values
}

The expression in the switch statement can be a variable or an expression that evaluates to a value. Each case block specifies a value to be compared against the expression. If the expression is equal to a case value, the code block following that case statement is executed. If none of the case values match the expression, the default block is executed (if it's present).

Here's an example of using the switch statement in Go:

dayOfWeek := "Monday"
switch dayOfWeek {
case "Monday":
    fmt.Println("Today is Monday.")
case "Tuesday":
    fmt.Println("Today is Tuesday.")
case "Wednesday":
    fmt.Println("Today is Wednesday.")
case "Thursday":
    fmt.Println("Today is Thursday.")
case "Friday":
    fmt.Println("Today is Friday.")
case "Saturday":
    fmt.Println("Today is Saturday.")
case "Sunday":
    fmt.Println("Today is Sunday.")
default:
    fmt.Println("Invalid day of the week.")
}

In this example, the program checks the value of the variable dayOfWeek and executes the appropriate code block based on its value. If dayOfWeek is equal to "Monday", the message "Today is Monday." is printed. If dayOfWeek is equal to "Tuesday", the message "Today is Tuesday." is printed, and so on. If dayOfWeek doesn't match any of the case values, the message "Invalid day of the week." is printed.

It's worth noting that each case block in a switch statement automatically breaks at the end of its code block. If you want to fall through to the next case block, you can use the fallthrough keyword. For example:

x := 2
switch x {
case 1:
    fmt.Println("x is 1")
    fallthrough
case 2:
    fmt.Println("x is 2")
    fallthrough
case 3:
    fmt.Println("x is 3")
default:
    fmt.Println("x is not 1, 2, or 3")
}

In this example, the program checks the value of the variable x and executes the code block for each case value that matches x, including the next one due to fallthrough. If x is equal to 2, the message "x is 2" is printed, and then the program falls through to the next case block, which prints "x is 3".