From: janis_papanagnou+ng@hotmail.com   
      
   On 22.10.2025 15:41, David Brown wrote:   
   > On 22/10/2025 13:44, Richard Harnden wrote:   
   >> On 22/10/2025 10:32, Janis Papanagnou wrote:   
   >>> On 22.10.2025 10:56, pozz wrote:   
   >>>>   
   >>>>> Switch statements without a default case can lead to unexpected   
   >>>>> behavior and incomplete handling of all possible cases. When a switch   
   >>>>> statement lacks a default case, if a value is encountered that does   
   >>>>> not match any of the specified cases, the program will continue   
   >>>>> execution without any defined behavior or handling.   
   >>>>   
   >>>> Maybe I misunderstood that sentence caused by my bad English. I knew   
   >>>> that in case the switch value is not present in any case inside the   
   >>>> switch, the program continues without doing anything (in the switch)   
   >>>> and   
   >>>> without any problem.   
   >>>>   
   >>>> int x = 3;   
   >>>> switch(x) {   
   >>>>    case 1: printf("Hello");break;   
   >>>>    case 2: printf("World");break;   
   >>>> }   
   >>>>   
   >>>> Will the program execution continue without any defined behaviour?   
   >   
   > Presumably you meant "without any undefined behaviour" ?  The code is   
   > fine - if no cases match and there is no default case, execution   
   > continues from the end of the switch statement.  Like most warnings,   
   > this is about a possible bug in the code - not a definite one.   
   >   
   >>>   
   >>> Your program fragment is well defined.   
   >>>   
   >>> What the poster certainly tried to express was that in case you   
   >>> haven't implemented a complete list of all possible cases and   
   >>> also not provided a 'default' to catch all non-specified cases,   
   >>> then you might get in troubles with your program, probably by   
   >>> possible oversights, future extensions, new data, and whatnot.   
   >>>   
   >>> Personally I have the habit to always define a default branch,   
   >>> and even if that default is impossible to reach you'll find an   
   >>> error message (like "internal error with unexpected value...")   
   >>> generated at that place.   
   >   
   > I don't think it is normally appropriate to add a default case unless   
   > you actually need it   
      
   Yes I was saying that I want it; I "need" it once errors slip in and   
   such a message or error log immediately clears the issue! (You might   
   be excluding some "needs" from your repertoire of necessities, okay.)   
      
   > - code that exists but can never be reached is   
   > untestable and can be confusing to people reading the code.  But   
   > sometimes it can be useful to add a "default : printf("Internal   
   > error...");" for debugging, however.   
      
   This printf error message or log entry is what I suggested. It isn't   
   confusing because it even _documents_ what's the case here. Rather,   
   a missing default leaves the reader with an unnecessary uncertainty.   
   YMMV.   
      
   Janis   
      
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