Swift Fallthrough Statement

by Online Tutorials Library July 14, 2022

Fallthrough Statement

Swift 4 fallthrough statementis used to simulate the behavior of Swift 4 switch to C/ C++ style switch. In Swift 4, the switch statementcompletes its execution as soon as the first matching case is completed unlike the C and C++ programming languages where falling through the bottom of subsequent cases happen.

Syntax of SwitchStatement in C/C++

  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);  }  

In the above code, we need a break statement to come out of a case statement, otherwise the execution control will fall through the subsequent case statements available below the matching case statement.

Syntax of Switch Statement in Swift 4

  switch expression {     case expression1 :        statement(s)  fallthrough /* optional */     case expression2, expression3 :        statement(s)  fallthrough /* optional */       default : /* Optional */        statement(s);  }  

In the above code, if we don’t usefallthrough statement, then the program will come out of the switch statement after executing the matching case statement.

Let’s see an example to make it clear.

Example: (Swift 4 example with fallthrough statement)

Let’s see how to use a switch statement in Swift 4 without fallthrough statement:

Example 1:

  var index = 4    switch index {     case 1:        print( “Hello Everyone”)     case 2,3 :        print( “This is tutoraspire”)     case 4 :        print( “tutoraspire is an educational portal”)     default :        print( “It is free to everyone”)  }  

Output:

tutoraspire is an educational portal

Example 2:

Let’s see how to use a switch statement in Swift 4 programming with fallthrough statement.

  var index = 10  switch index {     case 100:        print( “Hello Everyone”)        fallthrough     case 10,15 :        print( “This is tutoraspire”)        fallthrough     case 5 :        print( “tutoraspire is an educational portal”)     default :        print( “It is free to everyone”)  }  

Output:

This is tutoraspire  tutoraspire is an educational portal

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