Objective-C - 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 switch case.

Syntax

The syntax for a switch statement in Objective-C programming language is as follows −

switch(expression){
   case constant-expression  :
      statement(s);
      break; /* optional */
   case constant-expression  :
      statement(s);
      break; /* optional */
  
   /* you can have any number of case statements */
   default : /* Optional */
      statement(s);
}

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.

• The 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.

Flow Diagram

Example

#import <Foundation/Foundation.h>
 
int main () {
   
   /* local variable definition */
   char grade = 'B';

   switch(grade) {
   case 'A' :
      NSLog(@"Excellent!\n" );
      break;
   case 'B' :
   case 'C' :
      NSLog(@"Well done\n" );
      break;
   case 'D' :
      NSLog(@"You passed\n" );
      break;
   case 'F' :
      NSLog(@"Better try again\n" );
      break;
   default :
      NSLog(@"Invalid grade\n" );
   }
   
   NSLog(@"Your grade is  %c\n", grade );
   return 0;
}

When the above code is compiled and executed, it produces the following result −

2013-09-07 22:44:26.928 demo[17555] Well done
2013-09-07 22:44:26.929 demo[17555] Your grade is  B

Kickstart Your Career

Get certified by completing the course

Get Started