switchCase.adoc

title	categories	subCategories
switch...case	Structure	Control Structure

switch…​case statement

Description

Like if statements, switch case controls the flow of programs by allowing programmers to specify different code that should be executed in various conditions. In particular, a switch statement compares the value of a variable to the values specified in case statements. When a case statement is found whose value matches that of the variable, the code in that case statement is run.

The break keyword exits the switch statement, and is typically used at the end of each case. Without a break statement, the switch statement will continue executing the following expressions ("falling-through") until a break, or the end of the switch statement is reached.

Syntax

switch (var) {
  case label1:
    // statements
    break;
  case label2:
    // statements
    break;
  default:
    // statements
    break;
}

Parameters

var: a variable whose value to compare with various cases. Allowed data types: int, char.
label1, label2: constants. Allowed data types: int, char.

Returns

Nothing

Example Code

switch (var) {
  case 1:
    //do something when var equals 1
    break;
  case 2:
    //do something when var equals 2
    break;
  default:
    // if nothing else matches, do the default
    // default is optional
    break;
}

Notes and Warnings

If you need to declare a variable in a case, use curly brackets {} to define a scope within the case statement to avoid a "crosses initialization of" compiler error.

switch (var) {
  case 1:
    //do something when var equals 1
    break;
  case 2: {
    //do something when var equals 2
    int var2 = 1337; //to declare a variable you need the curly brackets
    break;
  }
  default:
    // if nothing else matches, do the default
    // default is optional
    break;
}

See also