switch-sase Statement

When we have many conditions to check, using multiple if-else statements may not be convenient.

Example

main


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void main() {
  String dayOfWeek = "Friday";
  if (dayOfWeek == "Monday") {
    print("Today is Monday.");
  } else if (dayOfWeek == "Tuesday") {
    print("Today is Tuesday.");
  } else if (dayOfWeek == "Wednesday") {
    print("Today is Wednesday.");
  } else if (dayOfWeek == "Thursday") {
    print("Today is Thursday.");
  } else if (dayOfWeek == "Friday") {
    print("Today is Friday.");
  }  else {
    print("Weekend");
  }
}

The code looks confusing, but we can make it more readable. For such cases, we can use the switch-case statement.

Switch-case Statement

The switch-case statement consists of several parts:

main


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switch(expresion) {
  case value_1: 
  //code to be executed
  case value_2: 
  //code to be executed
  .............
  default: //code to be executed if all cases are not matched
}

A switch-case statement is a construct that allows you to execute a block of code based on the value of a variable. The variable is called the switch variable. The switch variable is evaluated once, and the corresponding block of code is executed.

main


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void main() {
String dayOfWeek = "Friday";
switch (dayOfWeek) {
  case "Monday":
    print("Today is Monday.");
  case "Tuesday": 
    print("Today is Tuesday.");
  case "Wednesday":
    print("Today is Wednesday.");
  case "Thursday":
    print("Today is Thursday.");
  case "Friday":
    print("Today is Friday.");
  default:
    print("Weekend");
  }
}

In this example, the switch variable is dayOfWeek. The switch variable is evaluated once, and the corresponding code block is executed;
If one of the conditions is met, then after executing its code block, the subsequent conditions will not be checked, and the code blocks of those conditions will not be executed either;
In this case, the code block for dayOfWeek is "Friday". If the value of dayOfWeek does not match any of the cases, the default code block is executed. In this case, the default code block is "Weekend".

Tudo estava claro?

Obrigado pelo seu feedback!

Seção 3. Capítulo 4