C++ switch case

Switch Statement

A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each case.
Flow
Syntax The syntax for a switch statement in C++ is as follows:

The syntax of Switch case statement:

switch (expression)

 {
 case constant1: 

    group of statements 1;

 break;
 case constant2: 

    group of statements 2;

 break;
 . 

 .

 .

 default:

 default group of statements
}

The following rules apply to a switch statement:

◾ The expression used in a switch statement must have an integral or enumerated type, or be of a class type in which the class has a single conversion function to an integral or enumerated type.
◾ You can have any number of case statements within a switch. Each case is followed by the value to be compared to and a colon.
◾ Th constant-expression for a case must be the same data type as the variable in the switch, and it must be a constant or a literal.
◾ When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.
◾ When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.
◾ Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached.
◾ A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.

Both of the following code fragments have the same behavior: 

The switch statement is a bit peculiar within the C++ language because it uses labels instead of blocks. This forces us to put break statements after the group of statements that we want to be executed for a specific condition. 

Otherwise the remainder statements -including those corresponding to other labels- will also be executed until the end of the switch selective block or a break statement is reached.