Notes on Homework 3C

• You were given two examples of how your program should run.
  • In the specification page

  • bennett@mirkwood closed]$ main
    > Load A file1
    
    > Length A
    4
    
    > Print A
    Natalie Portman
    James T. Kirk
    Her Majesty The Queen
    Drake
    
    > Quit
    
    [bennett@mirkwood closed]$
    

  • This clearly shows a blank line after each command produces output.
  • And in the specific instructions for part C
  • There was an input and output file and instructions on how to use these.
  • Your output should match these!
• Your main should be your main.
• This is bad
  • I know I said that it should be small,
  • But a single line is not acceptable.

  • int main() {
        DoRealMain();
    }
            

  • This is worse

  • int main() {
        string Classes[MAX_CLASSES][CLASS_MAX];
        size_t ClassSizes[MAX_CLASSES];
    
        DoRealMain( Classes, ClassSizes);
    }
    

  • You should not declare variables where they are not used, which this does.
  • And it doesn't matter if you call it something other than DoRealMain
• Do not duplicate code.
  • If you find that you are writing the same code twice.
  • Or worse yet, you are copying and pasting code.
  • You are duplicating code.
  • Don't do this, write a function to handle this.
  • If you don't see how to write such a function, ASK

  • void DoPrint(string classes[5][], size_t sizes[5], string className){
        if (className=='A') {
            PrintArray(classes[0],size[0])
        } else if (className == 'B') {
            PrintArray(classes[1],size[1])
        } else if (className == 'C') {
            PrintArray(classes[2],size[2])
            ...
        }
    
    }
    void DoLoad(string classes[5][], size_t sizes[5], string className, string filename){
        if (className=='A') {
           LoadArray(classes[0],size[0], filename)
        } else if (className == 'B') {
           LoadArray(classes[1],size[1], filename)
        } else if (className == 'C') {
           LoadArray(classes[2],size[2], filename)
            ...
        }
    

  • Instead, do the following

    size_t IndexFromName(string className){
        size_t rv = MAX_CLASSES;
    
        if (className == "A") {
           rv = 0;
        } else if (className == "B") {
           rv = 1;
           ...
        }
    
        return rv;
    
    }
    
    void DoPrint(string classes[5][], size_t sizes[5], string className){
       index = IndexFromName(className);
       if (index < MAX_CLASSES):
           PrintArray(classes[index],size[index])
       }  else {
           // error message about class name
       }
    
    void DoLoad(string classes[5][], size_t sizes[5], string className, string filename){
       index = IndexFromName(className);
       if (index < MAX_CLASSES):
           LoadArray(classes[index],size[index], filename)
       }  else {
           // error message about class name
       }
    

  • In this case, DoLoad and DoPrint are similar, in the future we can avoid this as well, but for now this is ok.
• Please be careful when sharing code. Some of you are outright copying.
  • If you work with others, you must add this comment in your code.
  • If your code is the same, with only minor changes, this is plagiarism.
  • This will result in failure, for all involved, for the course.