switch with repeating cases?
CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Results 1 to 9 of 9

Thread: switch with repeating cases?

  1. #1
    Join Date
    Nov 2010
    Posts
    105

    Question switch with repeating cases?

    I have some cases in a switch statement sharing common code. Would this work?
    Code:
                    switch(mycase){
                        case 0: { code for case 0; } break;
                        case 1:
                        case 2: {
                            common code for case 1 and 2;
                        }
                        break;
                        case 2: {
                            code only for case 2;
                        }
                        break;
                    }

  2. #2
    Lindley is offline Elite Member Power Poster
    Join Date
    Oct 2007
    Location
    Fairfax, VA
    Posts
    10,888

    Re: switch with repeating cases?

    Yes, that will work fine.

  3. #3
    Join Date
    Nov 2010
    Posts
    105

    Re: switch with repeating cases?

    Thank you!

  4. #4
    Join Date
    Apr 1999
    Posts
    27,423

    Re: switch with repeating cases?

    Quote Originally Posted by acppdummy View Post
    I have some cases in a switch statement sharing common code. Would this work?
    Code:
                    switch(mycase){
                        case 0: { code for case 0; } break;
                        case 1:
                        case 2: {
                            common code for case 1 and 2;
                        }
                        break;
                        case 2: {
                            code only for case 2;
                        }
                        break;
                    }
    Code:
    void foo()
    {
       int mycase = 0;
       switch(mycase)
       {
          case 0: 
             break;
          case 1:
          case 2: 
          {
          }
          break;
          case 2: 
          {
          }
          break;
       }
    }
    Thank you for testing your code with Comeau C/C++!
    Tell others about http://www.comeaucomputing.com/tryitout !

    Your Comeau C/C++ test results are as follows:

    Comeau C/C++ 4.3.10.1 (Oct 6 2008 11:28:09) for ONLINE_EVALUATION_BETA2
    Copyright 1988-2008 Comeau Computing. All rights reserved.
    MODE:strict errors C++ C++0x_extensions

    "ComeauTest.c", line 13: error: case label value has already appeared in this
    switch at line 9
    case 2:
    ^

    1 error detected in the compilation of "ComeauTest.c".

    In strict mode, with -tused, Compile failed
    Regards,

    Paul McKenzie

  5. #5
    Join Date
    Nov 2010
    Posts
    105

    Question Re: switch with repeating cases?

    Well g++ didn't like it either:
    error: duplicate case value
    I suppose I could break it up by inserting some more switches like this?
    Code:
    switch(mycase){
                        case 0: { code for case 0; } break;
                        case 1:
                        case 2: {
                            common code for case 1 and 2;
                        }
                        break;
                }
                switch(mycase){
                        case 2: {
                            code only for case 2;
                        }
                        break;
                 }
    Or is there a way to turn off the "strict" mode in g++?

  6. #6
    Join Date
    Jan 2006
    Location
    Singapore
    Posts
    6,247

    Re: switch with repeating cases?

    I wonder if it would not just be simpler to write:
    Code:
    switch(mycase){
        case 0: { /* code for case 0; */ } break;
        case 1:
        case 2: {
            /* common code for case 1 and 2; */
            if (mycase == 2) {
                /* code only for case 2; */
            }
        }
        break;
    }
    C + C++ Compiler: MinGW port of GCC
    Build + Version Control System: SCons + Bazaar

    Look up a C/C++ Reference and learn How To Ask Questions The Smart Way
    Kindly rate my posts if you found them useful

  7. #7
    Join Date
    May 2009
    Posts
    2,413

    Re: switch with repeating cases?

    I would prefer to first separate the cases and then use functions for common code, like

    Code:
    switch (mycase){
        case 0:  
              // specific to case 0
           break;
        case 1:
           do12(); // common to both 1 and 2
              // specific to case 1
           break;
        case 2: {
           do12(); // common to both 1 and 2
              // specific to case 2
           break;
    }
    Last edited by nuzzle; January 19th, 2012 at 10:54 PM.

  8. #8
    Join Date
    Nov 2010
    Posts
    105

    Re: switch with repeating cases?

    Thanks everyone!

  9. #9
    Lindley is offline Elite Member Power Poster
    Join Date
    Oct 2007
    Location
    Fairfax, VA
    Posts
    10,888

    Re: switch with repeating cases?

    I missed that case 2 was in there twice, sorry.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Azure Activities Information Page

Windows Mobile Development Center


Click Here to Expand Forum to Full Width

This is a CodeGuru survey question.


Featured


HTML5 Development Center