Answer Happy

4 3. A palindrome is a word such as radar that is unchanged when it is spelt backwards. The C code below tests whether a string entered from the terminal is a palindrome or not. a 1 2 #include <stdio.h> #include <string.h> 4 5 6 int palindrome (char* word_p, int j) { char forwards [jl, backwards [j]; for (int i = 0; i<j; i++) forwards = *word_p++; for (int i = 0; i<n; i++) backwards = forwards (j-i-2]; return strcmp (forwards, backwards); } 10 11 12 13 14 15 16 17 18 19 int main(void) { char word [20]; printf("Please enter a word: "); scanf("%s", word); สี สี สสี สล 21 22 23 24 25 26 27 if (palindrome (word, strlen (word) +1) ==0) printf(" " & " is a palindrome! \a \n", word); else printf("\"%s" is not a palindrome \n", word); return 0; } a) How are header comments and inline comments added to C code? [2] b) Examine the code carefully and explain briefly how it works. You should include the sort of information that ought to be present in the missing header comments. [3] c) Write down a function prototype for the palindrome() function and explain why it would be needed if the main() function were moved to the top of a file? [3] d) What does the # symbol mean on lines 1 and 2? Give another example of the use of the # symbol in a C-program, other than with the "include" statement. [2] e) Examine line 9 of the code and explain what it is doing: What sort of variable is word_p and what are the * and ++ operators doing? [3] f) Explain line 23 of the code in detail, including the \" $s and la sequences. [3] g) If the string is identified as a palindrome, we may wish to append the word to an existing file called Palindromes.txt. Write down the code required to open, append and close the file. [4]