Case Expression Not Constant

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Case Expression Not Constant

 
0
  #1
Nov 2nd, 2009
When I try to compile this:

c++ Syntax (Toggle Plain Text) 
  1. void *BaseEnt::GetVar(char const *varname)
  2. {
  3. 	char name = *varname;
  4. 	switch(name)
  5. 	{
  6. 	case "id":
  7. 		return (void*)id;
  8. 	case "name":
  9. 		return (void*)name;
  10. 	case "count":
  11. 		return (void*)count;
  12. 	default:
  13. 		return (void*)NULL;
  14. 	}
  15. }

I get these errors:

C++ Syntax (Toggle Plain Text) 
  1. ------ Build started: Project: Test Classes, Configuration: Debug Win32 ------
  2. Compiling...
  3. classes.cpp
  4. c:\documents and settings\tom\my documents\visual studio 2008\projects\test classes\test classes\classes.cpp(25) : error C2051: case expression not constant
  5. c:\documents and settings\tom\my documents\visual studio 2008\projects\test classes\test classes\classes.cpp(27) : error C2051: case expression not constant
  6. c:\documents and settings\tom\my documents\visual studio 2008\projects\test classes\test classes\classes.cpp(29) : error C2051: case expression not constant
  7. c:\documents and settings\tom\my documents\visual studio 2008\projects\test classes\test classes\classes.cpp(33) : warning C4065: switch statement contains 'default' but no 'case' labels
  8. Build log was saved at "file://c:\Documents and Settings\tom\My Documents\Visual Studio 2008\Projects\Test Classes\Test Classes\Debug\BuildLog.htm"
  9. Test Classes - 3 error(s), 1 warning(s)
  10. ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I thought that things like "id" were constant because they're a litteral?

Any help would be appreciated.

PS. If you need more information on my problem, feel free to ask.
...
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0
  #2
Nov 2nd, 2009
the param to a switch cannot be a string.
It can only be an integer. To achieve what u are trying use if-else statement alongwith strcmp().
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-2
  #3
Nov 2nd, 2009
try this


c++ Syntax (Toggle Plain Text) 
  1. void *BaseEnt::GetVar(char const *varname)
  2. {
  3. 	char name = *varname;
  4. 	switch(name)
  5. 	{
  6. 	case 'id':                        //use ' not "
  7. 		return (void*)id;
  8. 	case 'name':                       //use ' not "
  9. 		return (void*)name;
  10. 	case 'count':                       //use ' not "  
  11. 		return (void*)count;
  12. 	default:
  13. 		return (void*)NULL;
  14. 	}
  15. }
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