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(a) Briefly explain the difference between
virtual functions and overloading. [2 marks]
(b) Consider the following definition
of the class String:
class String {
char* str;
int length;
public:
String();
String(char s[]);
int Length();
char* CharAt(int index);
}
(i) Add to the class a member function, called UpperCase, the signature
of which is given below, which converts all of the lower case elements
of the string to upper case, leaving upper case characters untouched.
You may wish to use the library function ToUpper, the signature of
which is given below, which takes in a single character and returns
its upper case equivalent. You are not required to implement ToUpper.
char ToUpper(char* x);
void String::UpperCase(); [3 marks]
(ii) Implement the function, StrCaseCompare, the signature of which
is given below, which takes in two references to string objects and
returns the result of comparing the two string objects, ignoring the
case of respective characters. If the two strings are the same irrespective
of case, the function should return 1, or 0 otherwise.
int StrCaseCompare(String a, String b); [5 marks]
(iii) Give an overloading of the operator ==, such that it compares
the two strings given to it as operands, and returns a pointer to
the first character in the strings which differ. Note that this test
should not be case independent. [5 marks]
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