Why Cant I Use Continue on the Default Answer in a Switch Statement
The switch statement is a multi-way branch statement. In simple words, the Java switch statement executes one statement from multiple conditions. It is like an if-else-if ladder statement. It provides an easy way to dispatch execution to different parts of code based on the value of the expression. Basically, the expression can be a byte, short, char, and int primitive data types. It basically tests the equality of variables against multiple values.
Note: Java switch expression must be of byte, short, int, long(with its Wrapper type), enums and string. Beginning with JDK7, it also works with enumerated types (Enums in java), the String class, and Wrapper classes.
Some Important Rules for Switch Statements
- There can be any number of cases just imposing condition check but remember duplicate case/s values are not allowed.
- The value for a case must be of the same data type as the variable in the switch.
- The value for a case must be constant or literal. Variables are not allowed.
- The break statement is used inside the switch to terminate a statement sequence.
- The break statement is optional. If omitted, execution will continue on into the next case.
- The default statement is optional and can appear anywhere inside the switch block. In case, if it is not at the end, then a break statement must be kept after the default statement to omit the execution of the next case statement.
Flow Diagram of Switch-Case Statement
Syntax: Switch-case
// switch statement switch(expression) { // case statements // values must be of same type of expression case value1 : // Statements break; // break is optional case value2 : // Statements break; // break is optional // We can have any number of case statements // below is default statement, used when none of the cases is true. // No break is needed in the default case. default : // Statements } Note: Java switch statement is a fall through statement that means it executes all statements if break keyword is not used, so it is highly essential to use break keyword inside each case.
Example: Consider the following java program, it declares an int named day whose value represents a day(1-7). The code displays the name of the day, based on the value of the day, using the switch statement.
Java
public class GFG {
public static void main(String[] args)
{
int day = 5 ;
String dayString;
switch (day) {
case 1 :
dayString = "Monday" ;
break ;
case 2 :
dayString = "Tuesday" ;
break ;
case 3 :
dayString = "Wednesday" ;
break ;
case 4 :
dayString = "Thursday" ;
break ;
case 5 :
dayString = "Friday" ;
break ;
case 6 :
dayString = "Saturday" ;
break ;
case 7 :
dayString = "Sunday" ;
break ;
default :
dayString = "Invalid day" ;
}
System.out.println(dayString);
}
}
Omitting the break Statement
A break statement is optional. If we omit the break, execution will continue on into the next case. It is sometimes desirable to have multiple cases without break statements between them. For instance, let us consider the updated version of the above program, it also displays whether a day is a weekday or a weekend day.
Example:
Java
public class GFG {
public static void main(String[] args)
{
int day = 2 ;
String dayType;
String dayString;
switch (day) {
case 1 :
dayString = "Monday" ;
break ;
case 2 :
dayString = "Tuesday" ;
break ;
case 3 :
dayString = "Wednesday" ;
break ;
case 4 :
dayString = "Thursday" ;
break ;
case 5 :
dayString = "Friday" ;
break ;
case 6 :
dayString = "Saturday" ;
break ;
case 7 :
dayString = "Sunday" ;
break ;
default :
dayString = "Invalid day" ;
}
switch (day) {
case 1 :
case 2 :
case 3 :
case 4 :
case 5 :
dayType = "Weekday" ;
break ;
case 6 :
case 7 :
dayType = "Weekend" ;
break ;
default :
dayType = "Invalid daytype" ;
}
System.out.println(dayString + " is a " + dayType);
}
}
Output
Tuesday is a Weekday
Nested Switch Case statements
We can use a switch as part of the statement sequence of an outer switch. This is called a nested switch. Since a switch statement defines its own block, no conflicts arise between the case constants in the inner switch and those in the outer switch.
Example:
Java
public class GFG {
public static void main(String[] args)
{
String Branch = "CSE" ;
int year = 2 ;
switch (year) {
case 1 :
System.out.println(
"elective courses : Advance english, Algebra" );
break ;
case 2 :
switch (Branch) {
case "CSE" :
case "CCE" :
System.out.println(
"elective courses : Machine Learning, Big Data" );
break ;
case "ECE" :
System.out.println(
"elective courses : Antenna Engineering" );
break ;
default :
System.out.println(
"Elective courses : Optimization" );
}
}
}
}
Output
elective courses : Machine Learning, Big Data
Example:
Java
public class GFG {
public enum Day { Sun, Mon, Tue, Wed, Thu, Fri, Sat }
public static void main(String args[])
{
Day[] DayNow = Day.values();
for (Day Now : DayNow) {
switch (Now) {
case Sun:
System.out.println( "Sunday" );
break ;
case Mon:
System.out.println( "Monday" );
break ;
case Tue:
System.out.println( "Tuesday" );
break ;
case Wed:
System.out.println( "Wednesday" );
break ;
case Thu:
System.out.println( "Thursday" );
break ;
case Fri:
System.out.println( "Friday" );
break ;
case Sat:
System.out.println( "Saturday" );
break ;
}
}
}
}
Output
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
This article is contributed by Gaurav Miglani. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
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