Golang program to implement switch statement on a strings

A switch statement in Golang is a control flow statement that enables you to run one block of Example: in response to various situations. Similar to if-else expressions, it can test several conditions more quickly. In this article, we will see how switch statement is implemented on strings in Go.

Method 1: Using default case as fallback option

In this method, if a match is detected, this program will verify the input variable, compare it to the cases, and execute the associated block of Example:; otherwise, it will run the default case block. Let’s see through the Example: and algorithm how it’s executed.

Algorithm

• Step 1 − Create a package main and declare fmt(format package) package in the program where main produces executable examples and fmt helps in formatting input and output.

• Step 2 − Create a function main and in that function create a variable called input value and initialize it with the string "option2".

• Step 3 − Use the variable input_value after the switch keyword.

• Step 4 − To specify the possibilities for the switch statement, use the case keyword followed by a string value.

• Step 5 − If the variable input_value matches the supplied case option, write the Example: that should be run.

• Step 6 − To handle any input that doesn't match one of the case options, use the default case as a fallback option.

• Step 7 − To print the chosen choice, use fmt.Println() function where ln means new line.

Example

In this program we will learn how to execute switch statement on strings using default case a fallback option

package main
import "fmt"

func main() {
   fmt.Println("The switch statement is executed like:")
   input_value := "option2"  //create an input value
   switch input_value {
   case "option1":
      fmt.Println("Option 1 selected")
   case "option2":
      fmt.Println("Option 2 selected")
   case "option3":
      fmt.Println("Option 3 selected")
   default:
      fmt.Println("Invalid option selected") //set a default case
   }
}

Output

The switch statement is executed like:
Option 2 selected

Method 2: Using fallthrough keyword

In this method,the fallthrough keyword is used to forward execution to the next case block in this example, if the input is "option2," the program will run the Example: block for, "option2" selected, and "option3" selected.

Algorithm

• Step 1 − Create a package main and declare fmt(format package) package in the program where main produces executable examples and fmt helps in formatting input and output.

• Step 2 − As per the above program repeat till step4 here and add fallthrough in option1,2 and 3.

• Step 3 − Use the default case as invalid option selected.

• Step 4 − With the help of fallthrough the execution of next block will continue.

• Step 5 − The output will be printed on the console using fmt.Println() function where ln means new line.

Example

In this example, we will see how we can execute switch statement on strings using fall through keyword.

package main
import "fmt"

func main() {
   input_value := "option2"  //create an input value
   fmt.Println("The switch statement is executed like:")
   switch input_value {
   case "option1":
      fmt.Println("Option 1 selected")
      fallthrough
   case "option2":
      fmt.Println("Option 2 selected")
      fallthrough
   case "option3":
      fmt.Println("Option 3 selected")
   default:
      fmt.Println("Invalid option selected")   //set default case
   }
}

Output

The switch statement is executed like:
Option 2 selected
Option 3 selected

Method 3: Using Maps

In this method, if a match is found, the program will run the associated function; otherwise, the default case block will be run. This program will verify the input variable and compare it with the keys in the map.

Algorithm

• Step 1 − Create a package main and declare fmt(format package) package in the program where main produces executable examples and fmt helps in formatting input and output.

• Step 2 − Create a main function and in that function create a variable called input_value and initialize it with the string "option2".

• Step 3 − Make a map with the name options where the values are the matching Example: blocks and the keys are the string choices.

• Step 4 − To determine whether the input variable is used as a key in the options map, use an if statement.

• Step 5 − Call the function saved as the key's value to run the matching Example: block if the key is present.

• Step 6 − Run a default case block that prints "Invalid choice selected" if the key is missing.

Example

In this program we will learn how to implement switch statement on strings with the help of maps.

package main
import "fmt"

func main() {
   input_value := "option2"    //create input value
   fmt.Println("The switch statement is executed like:")
   options := map[string]func(){       //create a map
      "option1": func() { fmt.Println("Option 1 selected") },
      "option2": func() { fmt.Println("Option 2 selected") },
      "option3": func() { fmt.Println("Option 3 selected") },
   }
   if fn, ok := options[input_value]; ok {
      fn()
   } else {
      fmt.Println("Invalid option selected")
   }
}

Output

The switch statement is executed like:
Option 2 selected

Conclusion

We executed the program of implementing switch statement on strings using three examples. In the first example we used simple switch case, in the second example we used fallthrough keyword and in the third example we used the map.