Switch Case in Dart

Switch Case In Dart

targets In this tutorial, you will learn to use dart switch case to control your program’s flow. A Switch case is used to execute the code block based on the condition.

switch(expression) {
    case value1:
        // statements
        break;
    case value2:
        // statements
        break;
    case value3:
        // statements
        break;
    default:
       // default statements
}

targets

How does switch-case statement work in dart

  • The expression is evaluated once and compared with each case value.
  • If expression matches with case value1, the statements of case value1 are executed. Similarly, case value 2 will be executed if the expression matches case value2. If the expression matches the case value3, the statements of case value3 are executed.
  • The break keywords tell dart to exit the switch statement because the statements in the case block are finished.
  • If there is no match, default statements are executed.
Info

Note: You can use a Switch case as an alternative to the if-else-if condition.

Replace If Else If With Switch In Dart

Here you can see the same program using if else if and switch in dart.

Example: Using If Else If

This example prints the day name based on the numeric day of the week using a if else if.

void main(){
   var dayOfWeek = 5;
if (dayOfWeek == 1) {
        print("Day is Sunday.");
  }
else if (dayOfWeek == 2) {
       print("Day is Monday.");
     }
else if (dayOfWeek == 3) {
      print("Day is Tuesday.");
     }
else if (dayOfWeek == 4) {
        print("Day is Wednesday.");
     }
else if (dayOfWeek == 5) {
        print("Day is Thursday.");
   }
else if (dayOfWeek == 6) {
        print("Day is Friday.");
    }
else if (dayOfWeek == 7) {
        print("Day is Saturday.");
}else{
        print("Invalid Weekday.");
     }
}

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Example Of Switch Statement

This example prints the day name based on the numeric day of the week using a switch case.

void main() {
  var dayOfWeek = 5;
  switch (dayOfWeek) {
    case 1:
        print("Day is Sunday.");
        break;
    case 2:
        print("Day is Monday.");
      break;
    case 3:
      print("Day is Tuesday.");
      break;
    case 4:
        print("Day is Wednesday.");
      break;
    case 5:
        print("Day is Thursday.");
      break;
    case 6:
        print("Day is Friday.");
      break;
    case 7:
        print("Day is Saturday.");
      break;
    default:
        print("Invalid Weekday.");
      break;
  }
}

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Info

Note: The syntax of switch statements is cleaner and much easier to read and write.

Switch Case On Strings

You can also use a switch case with strings. This program prints information based on weather value.

void main() {
 const weather = "cloudy";

  switch (weather) {
    case "sunny":
        print("Its a sunny day. Put sunscreen.");
        break;
    case "snowy":
        print("Get your skis.");
      break;
    case "cloudy":
    case "rainy": 
      print("Please bring umbrella.");
      break;
    default:
        print("Sorry I am not familiar with such weather.");
      break;
  }
}

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Switch Case On Enum

An enum or enumeration is used for defining value according to you. You can define your own type with a finite number of options. Here is the syntax for defining enum.

Syntax

enum enum_name { 
  constant_value1, 
  constant_value2, 
  constant_value3 
  }

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Example of Switch Using Enum In Dart

Enum plays well with switch statements. Let’s see an example using enum.

// define enum outside main function
enum Weather{ sunny, snowy, cloudy, rainy}
// main method
void main() {
 const weather = Weather.cloudy;
  
  switch (weather) {
    case Weather.sunny:
        print("Its a sunny day. Put sunscreen.");
        break;
    case Weather.snowy:
        print("Get your skis.");
      break;
    case Weather.rainy:
    case Weather.cloudy:
      print("Please bring umbrella.");
      break;
    default:
        print("Sorry I am not familiar with such weather.");
      break;
  }
}

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Video

Watch our video on the switch case in Dart.