Introduction to Switch Statement
The switch is sometimes classified as a selection statement. The switch statement selects from among pieces of code based on the value of an integral expression.
Integral-selector is an expression that produces an integral value. The switch compares the result of integral-selector to each integral-value. If it finds a match, the corresponding statement (simple or compound) executes. If no match occurs, the default statement executes. You will notice in the above definition that each case ends with a break, which causes execution to jump to the end of the switch body. This is the conventional way to build a switch statement, but the break is optional.
If it is missing, the code for the following case statements execute until a break is encountered. Although you don’t usually want this kind of behavior, it can be useful to an experienced programmer. Note the last statement, following the default, doesn’t have a break because the execution just falls through to where the break would have taken it anyway. You could put a break at the end of the default statement with no harm if you considered it important for style’s sake. The switch statement is a clean way to implement multi-way selection (i.e., selecting from among a number of different execution paths), but it requires a selector that evaluates to an integral value such as int or char. If you want to use, for example, a string or a floating-point number as a selector, it won’t work in a switch statement. For non-integral types, you must use a series of if statements.
Syntax
switch (integral-selector) {
case integral-value1 : statement; break;
case integral-value2 : statement; break;
case integral-value3 : statement; break;
case integral-value4 : statement; break;
case integral-value5 : statement; break;
// ...
default: statement;
}
Example
1. /**
2. * @(#)SwitchStatementDemo.java
3. *
4. *
5. * @author
6. * @version 1.00 2009/11/6
7. */
8.
9. public class SwitchStatementDemo {
10.
11. /**
12. * Creates a new instance of <code>SwitchStatementDemo</code>.
13. */
14. public SwitchStatementDemo() {
15. }
16.
17. /**
18. * @param args the command line arguments
19. */
20. public static void main(String[] args) {
21. // TODO code application logic here
22.
23. int day = 5;
24.
25. switch (day) {
26.
27. case 1:
28. System.out.println("Monday");
29. break;
30. case 2:
31. System.out.println("Tuesday");
32. break;
33. case 3:
34. System.out.println("Wednesday");
35. break;
36. case 4:
37. System.out.println("Thursday");
38. break;
39. case 5:
40. System.out.println("Friday");
41. break;
42. case 6:
43. System.out.println("Saturdary");
44. break;
45. case 7:
46. System.out.println("Sunday");
47. break;
48.
49. default:
50. System.out.println("Please enter correct number.");
51.
52.
53. }
54. }
55. }
Output
Friday
