Switch statement

In computer programming languages, a switch statement is a type of selection control mechanism used to allow the value of a variable or expression to change the control flow of program execution via search and map.

Switch statements function somewhat similarly to the if statement used in programming languages like C/C++, C#, Visual Basic .NET, Java and exist in most high-level imperative programming languages such as Pascal, Ada, C/C++, C#,^{: 374–375} Visual Basic .NET, Java,^{: 157–167} and in many other types of language, using such keywords as switch, case, select or inspect.

Switch statements come in two main variants: a structured switch, as in Pascal, which takes exactly one branch, and an unstructured switch, as in C, which functions as a type of goto. The main reasons for using a switch include improving clarity, by reducing otherwise repetitive coding, and (if the heuristics permit) also offering the potential for faster execution through easier compiler optimization in many cases.

switch (age) {
  case 1:  printf("You're one.");            break;
  case 2:  printf("You're two.");            break;
  case 3:  printf("You're three.");
  case 4:  printf("You're three or four.");  break;
  default: printf("You're not 1, 2, 3 or 4!");
}