switch statement
The switch statement is a multiway branch statement.
It provides a better alternative than a large series of
if-else-if statements. Here is the general form of a switch statement:
switch (expression) {
case value1:
statement sequence
break;
case value2:
statement sequence
break;
.
.
.
case valueN:
statement sequence
break;
default:
default statement sequence
}
Duplicate case values are not allowed.
A
break statement jumps out of switch statement to the first line that follows the entire switch statement.Here is a simple example that uses a
switch statement:
public class Main {
public static void main(String args[]) {
for (int i = 0; i < 6; i++)
switch (i) {
case 0:
System.out.println("i is zero.");
break;
case 1:
System.out.println("i is one.");
break;
case 2:
System.out.println("i is two.");
break;
case 3:
System.out.println("i is three.");
break;
default:
System.out.println("i is greater than 3.");
}
}
}
The output produced by this program is shown here:
i is zero.
i is one.
i is two.
i is three.
i is greater than 3.
i is greater than 3.
The break statement is optional
If you omit the break, execution will continue on into the next case.
For example, consider the following program:
public class Main {
public static void main(String args[]) {
for (int i = 0; i < 12; i++)
switch (i) {
case 0:
case 1:
case 2:
case 3:
case 4:
System.out.println("i is less than 5");
break;
case 5:
case 6:
case 7:
case 8:
case 9:
System.out.println("i is less than 10");
break;
default:
System.out.println("i is 10 or more");
}
}
}
This program generates the following output:
i is less than 5
i is less than 5
i is less than 5
i is less than 5
i is less than 5
i is less than 10
i is less than 10
i is less than 10
i is less than 10
i is less than 10
i is 10 or more
i is 10 or more
Nested switch Statements
For example, the following fragment is a valid nested switch statement.
public class Main {
public static void main(String args[]) {
for (int i = 0; i < 6; i++)
switch(i) {
case 0:
switch(i+1) { // nested switch
case 0:
System.out.println("target is zero");
break;
case 1:
System.out.println("target is one");
break;
}
break;
case 2: // ...
}
}
}
The output:
target is one