2-Debugging.txt

Part Two: Fixing the Bugs
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Understanding the code

  1) Explain why this program uses the exclamation operator with the
     strcmp() function.
     ans: when two strings are identical, the function will return 0, so in order to execute the statement below the condition, ! should be used to turn 0 to 1. 

  2) Explain why the 'LENGTH' macro returns the length of an array.
     Would it work with a pointer to a dynamically allocated array? (Hint:
     understand sizeof).

sizeof(arr) returns the total memory used for the whole array and sizeof(*arr) returns the memory used for the first element so it will return the number of elements in the array when sizeof(arr)/sizeof(*arr).
No.sizeof() doesn't work to a dynamic array since it dosen't return the whole number of memory in the numerator but return the size of the pointer. 

Bug hunting

  3) Explain and fix the logical flow bug within the switch statement.
     (What happens when the -h option is used?)
      we should add "break" statement after the case"h" is executed.Without break, when -h   option is used, the default will also be executed after the case"h" is executed.

  4) Explain and fix the argument parsing error. (Why is entrycount never
     zero?)
     because when we type ./main to execute the program, "main" will also be considered as a word that stored in entries, which causes entrycount will never be zero. In order to fix that, we should add "argv++" before while statement.
    

  5) Fix print_result() to print results correctly and in the same order
     as the words were specified on the command line.  Explain your solution.
   In the function, in order to print the next word in entries arry, we should add entries++ after printing the result of the previous word, but this statement isn't in the original function so only the first word in the array is printed.