C++ help thank you! This project is to work on the assignment I\'ve done before,
ID: 3776910 • Letter: C
Question
C++ help thank you!
This project is to work on the assignment I've done before, I posted the previous assignment's requirement and my code for that one below so it might seems kind of lengthy......
(What we need to do)
you'll be making the following refinements to the class that you wrote in the last assignment. All the requirements from that class still apply. For example, all myStrings must always be stored in a dynamic array that is exactly the correct size to store the string.
Extraction Operator
Just like the >> operator that reads C-strings, your >> operator should skip any leading spaces and then read characters into the string up to the first whitespace character.
For reasons of convenience, we will impose a limit of 127 on the number of characters this function will read. This is so you can temporarily read into a non-dynamic array and then copy what you need into your data member, which will be a dynamic array. Note that this does not mean that all myStrings will always have a maximum of 127 characters. For example, you might get a myString with more than 127 characters by using the myString constructor or by concatenating two myStrings.
Hint: Don't try to read character by character in a loop. Use the extraction operator to do the reading of the input into a non-dynamic array, then use strcpy() to copy it into your data member. Make sure to allocate the correct amount of memory.
Hint: if you use the extraction operator as suggested above, you will not have to skip leading whitespace, because the extraction operator does that for you.
A read() function
The read() function will allow the client programmer to specify the delimiting character (the one to stop at instead of the first space). This will be a void function that will take two arguments, a stream and the delimiting character. It should not skip leading spaces. The limit of 127 characters imposed on the >> function above also applies to this function.
Hint: Don't try to read character by character in a loop. Use the in.getline() function to do the reading of the input into a non-dynamic array, then use strcpy() to copy it into your data member.
Concatenation Operator
Overload the + operator to do myString concatenation. The operator must be able to handle either myString objects or C-strings on either side of the operator. Be careful with the memory management here. You'll have to allocate enough memory to hold the new myString. I suggest using strcpy() to get the left operand into the result myString, and then strcat() to append the right operand. Both strcpy() and strcat() should be used as if they are void, even though they do have return values.
Combined Concatenation/Assignment Operator
Overload the shorthand += to combine concatenation and assignment. Only myStrings can be on the left-hand side of a += operation, but either myStrings or C-strings may appear on the right side. If you pay close attention to the += operator from the feetInches class, these may be the easiest points of the semester.
Add Documentation
Header File: In the case of a class, the header file should begin with a (typically) very large header comment. This comment should include a general description of the class (so a client programmer can tell right away whether she wants to use it), followed by a listing of all of the prototypes of public members, each with pre and post conditions. Note that this list of prototypes is still part of the comment. You will have to list the prototypes again in the code below this header comment! You are required to use pre/post conditions to document your public member functions. Do not include any comments regarding the implementation details in the header file! This very large comment will then be followed by the header file code (e.g. the class declaration), with no comments.
Implementation File: In the implementation file you should start with a class invariant. (I don't expect you to have prior knowledge of what a class invariant is. The description that follows should suffice.) The class invariant will include a description of the private data members and how they are used, as well as a statement of anything that you guarantee will always be true for class objects (for example: "fraction objects will always be stored in lowest terms"). Aside from the class invariant, the only comments you will need in your implementation file are comments on the implementation of complex functions, and comments on private functions (which do not get comments in the header file).
Comments in the header file will follow the following pattern.
Name your source code files mystring.h and mystring.cpp.
Data file:
Client program:
Correct output:
==============================================
Previous work and requirement:
See also client program and correct output.
Clint program
Correct output
Requirements:
Write a string class. To avoid conflicts with other similarly named classes, we will call our version myString. This object is designed to make working with sequences of characters a little more convenient and less error-prone than handling raw c-strings, (although it will be implemented as a c-string behind the scenes). The myString class will handle constructing strings, reading/printing, and accessing characters. In addition, the myString object will have the ability to make a full deep-copy of itself when copied.
Your class must have only one data member, a c-string implemented as a dynamic array. In particular, you must not use a data member to keep track of the size or length of the myString.
This is the first part of a two part assignment. In the next assignment you will be making some refinements to the class that you create in this assignment. For example, no documentation is required this week, but full documentation will be required next week.
Here is a list of the operations this class must support:
A length member function which returns the number of characters in the string. Use strlen().
Construction of a myString from a const c-string. You should copy the string data, not just store a pointer to an argument passed to the constructor. Constructing a myString with no arguments creates an empty myString object (i.e. ""). A myString object should be implemented efficiently (space-wise) which is to say you should not have a fixed-size buffer of chars, but instead allocate space for chars on an as-needed basis. Use strcpy().
Printing a myString to a stream using an overloaded << (insertion) operator, which should simply print out its characters. Use <<.
Your myString object should overload the square brackets [ ] operator to allow direct access to the individual characters of the string. This operation should range-check and assert if the index is out of bounds. You will write two versions of the [ ] operator, a const version that allows read access to the chars, and a non-const version that returns the client a reference to the char so they can change the value.
All six of the relational operators (<, <=, >, >=, ==, !=) should be supported. They should be able to compare myString objects to other myStrings as well as myStrings to c-strings. The ordering will be based on ASCII values. You can think of this as essentially alphabetical order; however, because of the way that ASCII values are defined, uppercase letters will always come before lowercase letters, and punctuation will make things even more complicated. Confused? You don't need to worry about any of this: just use the results of calling the strcmp() function. myStrings or c-strings should be able to appear on either side of the comparison operator.
Of course, you'll also need to include the four functions discussed in the lesson that are always required in classes that use dynamic memory. (These functions, excluding the default constructor, are otherwise known as the "big-three".)
You may use all of the c-string functionality provided by C++. This will include the strlen(), strcmp(), and strcpy() functions, along with the overloaded insertion operator for c-strings. These functions are all covered in detail in the text. When you use strcpy() treat it as a void function despite the fact that it has a return value. Do not use strncpy(), strncat(), or strncmp() since they are not implemented in all versions of C++. You may NOT use anything from the C++ string class!!
You must place your header file and implementation file in a namespace. Normally one would call a namespace something more likely to be unique, but for purposes of convenience we will call our namespace "cs_mystring".
My work on this one:
myString.h
#ifndef myString_H
#define myString_H
#include
#include
using namespace std;
namespace cs_myString {
class myString {
public:
/*
Preconditon: Takes no parameter and return nothing.
Postcondition: Initialize data member-'desc' with memory of size 1 and
copy empty string to it
*/
myString();
/*
Preconditon: Takes one argument - pointer to char object 'inDesc' and
is kept const
Postcondition: object is created with size accordingly with specified
object pointer given at input
*/
myString(const char *inDesc);
/*
Preconditon: Takes one argument - reference to myString object 'right'
and is kept const
Postcondition: object is created with size accordingly with specified
object reference given at input
*/
myString(const myString& right);
/*
Preconditon: an myString object exist with valid length
Postcondition: myString object is destroyed
*/
~myString();
/*
Preconditon: Input argument contains address to myString object:-Right.
Postcondition: object is copied with size accordingly with specified
object reference given at input
*/
myString operator=(const myString& right);
/*
Preconditon: Input argument contains address to myString object:-Right.
Postcondition: returns pointer to this object which was created by
combination of concatenation and assignment operator
*/
myString operator+=(const myString& right);
/*
Preconditon: Input argument contains pointer to char object:-Right.
Postcondition: returns pointer to this char object which was created by
combination of concatenation and assignment operator
*/
myString operator+=(const char *right);
/*
Preconditon: length donot take any argument
Postcondition: returns length of myString object
*/
int length() const;
OR
/*
Precondition: The out of ostream object is waiting to receive the
myString output.
Postcondition: myString source has been passed by reference to the
ostream out and is kept const.
*/
friend ostream& operator<<(ostream& out, const myString& source);
/*
Precondition: The in of istream object is waiting to receive the
myString input.
Postcondition: myString source has been passed by reference into
the istream 'in'.
*/
friend istream& operator>>(istream& in, myString &source);
/*
Precondition:- Input argument contains address to two myString object:
- Left and Right.
Postcondition: function return's true, if Left < Right, else it return's
false.
*/
friend bool operator<(const myString &Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's true, if Left <= Right, else it
return's false.
*/
friend bool operator<=(const myString &Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's true, if Left == Right, else it
return's false.
*/
friend bool operator==(const myString &Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's true, if Left != Right, else it
return's false.
*/
friend bool operator!=(const myString &Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's true, if Left >= Right, else it
return's false.
*/
friend bool operator>=(const myString &Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's true, if Left > Right, else it
return's false.
*/
friend bool operator>(const myString &Left, const myString &Right);
/*
Precondition:- Input argument contains address to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left < Right, else it
return's false.
*/
friend bool operator<(const myString &Left, const char* Right);
/*
Precondition:- Input parameters contains reference to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left <= Right, else it
return's false.
*/
friend bool operator<=(const myString &Left, const char* Right);
/*
Precondition:- Input parameters contains reference to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left == Right, else it
return's false.
*/
friend bool operator==(const myString &Left, const char* Right);
/*
Precondition:- Input parameters contains reference to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left != Right, else it
return's false.
*/
friend bool operator!=(const myString &Left, const char* Right);
/*
Precondition:- Input parameters contains reference to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left >= Right, else it
return's false.
*/
friend bool operator>=(const myString &Left, const char* Right);
/*
Precondition:- Input parameters contains reference to myString object
and c_string:- Left and Right.
Postcondition: function return's true, if Left > Right, else it
return's false.
*/
friend bool operator>(const myString &Left, const char* Right);
/*
Precondition:- Input argument contains address to c_string and myString
object:- Left and Right.
Postcondition: function return's true, if Left < Right, else it return's
false.
*/
friend bool operator<(const char* Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to c_string and
myString object:- Left and Right.
Postcondition: function return's true, if Left <= Right, else it
return's false.
*/
friend bool operator<=(const char* Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to c_string and
myString object:- Left and Right.
Postcondition: function return's true, if Left == Right, else it
return's false.
*/
friend bool operator==(const char* Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to c_string and
myString object:- Left and Right.
Postcondition: function return's true, if Left != Right, else it
return's false.
*/
friend bool operator!=(const char* Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to c_string and
myString object:- Left and Right.
Postcondition: function return's true, if Left >= Right, else it
return's false.
*/
friend bool operator>=(const char* Left, const myString &Right);
/*
Precondition:- Input parameters contains reference to c_string and
myString object:- Left and Right.
Postcondition: function return's true, if Left > Right, else it
return's false.
*/
friend bool operator>(const char* Left, const myString &Right);
/*
Preconditon: Input argument contains two argument, a stream and the
delimiting character.
Postcondition: Reads character by character in a loop. Use the in.
getline() function to do the reading of the input into a non-dynamic
array, then use strcpy() to copy it into your data member. return void.
*/
void read(istream& inString,char delim);
/*
Precondition:- Input parameters contains reference to two myString
object:- Left and Right.
Postcondition: function return's addition of two myString objects.
*/
friend const myString operator+(const myString &left, const myString &right);
/*
Preconditon: Input argument contains value of index.
Postcondition: Returns the index to myString specifying the char to
that location which is const.
*/
char operator[](int index) const;
/*
Preconditon: Input argument contains value of index.
Postcondition: Returns the index to myString specifying the char to
that location.
*/
char& operator[](int index);
private:
char *desc;
};
}
#endif
myString.cpp
#include
#include "myString.h"
using namespace std;
namespace cs_myString {
/*
This part initialize desc with memory of size 1 and copy empty string to it.
*/
myString::myString() {
desc = new char[1];
strcpy(desc, "");
}
/*
The parameterized constructor takes pointer argument pointing to the object.
*/
myString::myString(const char *inDesc) {
desc = new char[strlen(inDesc) + 1];
strcpy(desc, inDesc);
}
/*
The parameterized construtor takes one reference parameter the address to the
object location.
*/
myString::myString(const myString& right) {
desc = new char[strlen(right.desc) + 1];
strcpy(desc, right.desc);
}
myString::~myString() {
delete [] desc;
}
/*
This part has the overloaded operator = that takes one argument reference to
object and is kept const.
*/
myString myString::operator=(const myString& right) {
if (this != &right) {
delete [] desc;
desc = new char[strlen(right.desc) + 1];
strcpy(desc, right.desc);
}
return *this;
}
/*
These parts overloaded operators, and are able to compare myString objects to
other myStrings as well as myStrings to c-strings
*/
bool operator==(const myString& left, const myString& right) {
return strcmp(left.desc, right.desc) == 0;
}
bool operator==(const myString& left, const char* right) {
return strcmp(left.desc, right) == 0;
}
bool operator==(const char* left, const myString& right) {
return strcmp(left, right.desc) == 0;
}
bool operator<(const myString& left, const myString& right) {
return strcmp(left.desc, right.desc) < 0;
}
bool operator<(const myString& left, const char* right) {
return strcmp(left.desc, right) < 0;
}
bool operator<(const char* left, const myString& right) {
return strcmp(left, right.desc) < 0;
}
bool operator!=(const myString& left, const myString& right) {
return !(left == right);
}
bool operator!=(const myString& left, const char* right) {
return !(left == right);
}
bool operator!=(const char* left, const myString& right) {
return !(left == right);
}
bool operator>(const myString& left, const myString& right) {
return !(left == right) && !(left < right);
}
bool operator>(const myString& left, const char* right) {
return !(left == right) && !(left < right);
}
bool operator>(const char* left, const myString& right) {
return !(left == right) && !(left < right);
}
bool operator<=(const myString& left, const myString& right) {
return left < right || left == right;
}
bool operator<=(const myString& left, const char* right) {
return left < right || left == right;
}
bool operator<=(const char* left, const myString& right) {
return left < right || left == right;
}
bool operator>=(const myString& left, const myString& right) {
return !(left < right);
}
bool operator>=(const myString& left, const char* right) {
return !(left < right);
}
bool operator>=(const char* left, const myString& right) {
return !(left < right);
}
/*
This part return length of string in int.
*/
int myString::length() const {
return (int) strlen(desc);
}
/*
This part overloaded operator << function takes computed address of source and
is passed to out object of ostream to display results.
*/
ostream& operator<<(ostream& out, const myString& source) {
out << source.desc;
return out;
}
/*
This part overload The Square Brackets returns a const char for the index returned.
*/
char myString::operator[](int index) const {
assert(index >= 0 && index < strlen(desc));
return desc[index];
}
/*
This part overload The Square Brackets returns an reference to char at that
index.
*/
char& myString::operator[](int index) {
assert(index >= 0 && index < strlen(desc));
return desc[index];
}
/*
This part overloaded Extraction >> operator function takes address of source.
*/
istream& operator>>(istream& in, myString &source)
{
char temp[127];
delete [] source.desc;
in >> temp;
source.desc = new char[strlen(temp) + 1 ];
strcpy(source.desc, temp);
return in;
}
/*
The read() function returns void and takes two arguments, a stream and
the delimiting character. It does not skip leading spaces.
*/
void myString::read(istream &source, char delim)
{
char temp[127];
delete [] desc;
source.getline(temp,127,delim);
desc = new char[strlen(temp) + 1 ];
strcpy(desc,temp);
}
/*
This part overloaded operator + function, takes two parameter which is reference to
myString 'left' & 'right' and is declared const.
*/
const myString operator+(const myString &left, const myString &right)
{
myString temp;
temp = new char[strlen(left.desc) + strlen(right.desc) + 1];
strcpy(temp.desc, left.desc);
strcat(temp.desc, right.desc);
return temp;
}
/*
This part overloaded the shorthand += to combine concatenation and assignment.
*/
myString myString::operator+=(const myString& right)
{
myString temp;
temp = new char[strlen(right.desc) + 1];
delete [] desc;
desc = new char[strlen(temp.desc) + strlen(right.desc) + 1];
strcat(desc, right.desc);
return *this;
}
/*
This part overloaded the shorthand += to combine concatenation and assignment.
*/
myString myString::operator+=(const char *right)
{
myString temp;
temp = new char[strlen(right) + 1];
delete [] desc;
desc = new char[strlen(temp.desc) + strlen(right) + 1];
strcat(desc, right);
return *this;
}
}
Explanation / Answer
Mystring.cpp:
#define MYSTRING_H
#ifndef MYSTRING_H
#include <iostream>
using namespace std;
class MyString {
public:
MyString(); //1st
MyString(cons char *inString); //2nd
MyString operator=(cons MyString right); //3rd
MyString(cons MyString &right); //4th
~MyString(); //the destructor
int length()cons;
friend ostream& operator<<(ostream& out,cons MyString &outString);
friend istream& operator>>(istream& in,MyString &inString);
void read(istream& inString,char delimit);
char& operator[](int index);
char operator[](int index)cons;
friend MyString operator+(cons MyString left,cons MyString right);
MyString& operator+=( cons MyString &right);
friend bool operator<(cons MyString &left, cons MyString &right);
friend bool operator<=(cons MyString &left, cons MyString &right);
friend bool operator>=(cons MyString &left, cons MyString &right);
friend bool operator>(cons MyString &left, cons MyString &right);
friend bool operator==(cons MyString &left, cons MyString &right);
friend bool operator!=(cons MyString &left, cons MyString &right);
private:
char * string;
};
#endif
/*
* -------------------
* These functions are designed to help you test your MyString objects,
* as well as show the client usage of the class.
*
* The BasicTest function builds an array of strings using various
* constructor options and prints them out. It also uses the String
* stream operations to read some strings from a data file.
*
* The RelationTest function checks out the basic relational operations
* (==, !=, <, etc) on Strings and char *s.
*
* The ConcatTest functions checks the overloaded + and += operators that
* do string concatenation.
*
* The CopyTest tries out the copy constructor and assignment operators
* to make sure they do a true deep copy.
*
* Although not exhaustive, these tests will help you to exercise the basic
* functionality of the class and show you how a client might use it.
*
* While you are developing your MyString class, you might find it
* easier to comment out functions you are ready for, so that you don't
* get lots of compile/link complaints.
*/
#include "mystring.h"
#include <cctype> // for toupper()
#include <fstream>
#include <cassert>
#include <string>
#include <iostream>
using namespace std;
bool eof(istream& in);
void BasicTest();
void RelationTest();
void ConcatTest();
void CopyTest();
MyString AppendTest(cons MyString& ref, MyString val);
int main()
{
BasicTest();
RelationTest();
ConcatTest();
CopyTest();
}
bool eof(istream& in)
{
char ch;
in >> ch;
in.putback(ch);
return !in;
}
void BasicTest()
{
cout << "----- Testing basic String creation & printing" << endl;
cons MyString strs[] =
{MyString("Wow"), MyString("C++ is neat!"),
MyString(""), MyString("a-z")};
for (int i = 0; i < 4; i++){
cout << "string [" << i <<"] = " << strs[i] << endl;
}
cout << endl << "----- Now reading MyStrings from file" << endl;
cout << endl << "----- first, word by word" << endl;
ifstream in("string.data");
assert(in);
while (!eof(in)) {
MyString s; // this will creates an empty string
if (in.peek() == '#') { // peek at char, comments start with #
in.ignore(128, ' '); // To skip this line, it's a comment
} else {
in >> s;
cout << "Read string = " << s << endl;
}
}
in.close();
cout << endl << "----- now, line by line" << endl;
ifstream in2("mystring.txt");
assert(in2);
while (!eof(in2)) {
MyString s; // creates an empty string
if (in2.peek() == '#') { // peek at char, comments start with #
in2.ignore(128, ' '); // skip this line, it's a comment
} else {
s.read(in2, ' ');
cout << "Read string = " << s << endl;
}
}
in2.close();
cout << endl << "----- Testing access to characters (using cons)" <<
endl;
cons MyString s("abcdefghijklmnopqsrtuvwxyz");
cout << "Whole string is " << s << endl;
cout << "now char by char: ";
for (int i = 0; i < s.length(); i++){
cout << s[i];
}
cout << endl << "----- Testing access to characters (using non-cons)"
<< endl;
MyString s2("abcdefghijklmnopqsrtuvwxyz");
cout << "Start with " << s2;
for (int i = 0; i < s.length(); i++){
s2[i] = toupper(s2[i]);
}
cout << " and convert to " << s2 << endl;
}
void RelationTest()
{
cout << " ----- Testing relational operators between MyStrings ";
cons MyString strs[] =
{MyString("app"), MyString("apple"), MyString(""),
MyString("Banana"), MyString("Banana")};
for (int i = 0; i < 4; i++) {
cout << "Comparing " << strs[i] << " to " << strs[i+1] << endl;
cout << " Is left < right? " << (strs[i] < strs[i+1]) << endl;
cout << " Is left <= right? " << (strs[i] <= strs[i+1]) << endl;
cout << " Is left > right? " << (strs[i] > strs[i+1]) << endl;
cout << " Is left >= right? " << (strs[i] >= strs[i+1]) << endl;
cout << " Does left == right? " << (strs[i] == strs[i+1]) << endl;
cout << " Does left != right ? " << (strs[i] != strs[i+1]) << endl;
}
cout << " ----- Testing relations between MyStrings and char * ";
MyString s("he");
cons char *t = "hello";
cout << "Comparing " << s << " to " << t << endl;
cout << " Is left < right? " << (s < t) << endl;
cout << " Is left <= right? " << (s <= t) << endl;
cout << " Is left > right? " << (s > t) << endl;
cout << " Is left >= right? " << (s >= t) << endl;
cout << " Does left == right? " << (s == t) << endl;
cout << " Does left != right ? " << (s != t) << endl;
MyString u("wackity");
cons char *v = "why";
cout << "Comparing " << v << " to " << u << endl;
cout << " Is left < right? " << (v < u) << endl;
cout << " Is left <= right? " << (v <= u) << endl;
cout << " Is left > right? " << (v > u) << endl;
cout << " Is left >= right? " << (v >= u) << endl;
cout << " Does left == right? " << (v == u) << endl;
cout << " Does left != right ? " << (v != u) << endl;
}
void ConcatTest()
{
cout << " ----- Testing concatentation on MyStrings ";
cons MyString s[] =
{MyString("outrageous"), MyString("milk"), MyString(""),
MyString("cow"), MyString("bell")};
for (int i = 0; i < 4; i++) {
cout << s[i] << " + " << s[i+1] << " = " << s[i] + s[i+1] << endl;
}
cout << " ----- Testing concatentation between MyString and char * ";
cons MyString a("abcde");
cons char *b = "XYZ";
cout << a << " + " << b << " = " << a + b << endl;
cout << b << " + " << a << " = " << b + a << endl;
cout << " ----- Testing shorthand concat/assign on MyStrings ";
MyString s2[] =
{MyString("who"), MyString("what"), MyString("WHEN"),
MyString("Where"), MyString("why")};
for (int i = 0; i < 4; i++) {
cout << s2[i] << " += " << s2[i+1] << " = ";
cout << (s2[i] += s2[i+1]) << endl;
}
cout << " ----- Testing shorthand concat/assign using char * ";
MyString u("I love ");
cons char *v = "programming";
cout << u << " += " << v << " = ";
cout << (u += v) << endl;
}
MyString AppendTest(cons MyString& ref, MyString val)
{
val[0] = 'B';
return val + ref;
}
void CopyTest()
{
cout << " ----- Testing copy constructor and operator= on MyStrings ";
MyString orig("cake");
MyString copy(orig); // This will be invoking copy constructor
copy[0] = 'f'; // change first letter of the *copy*
cout << "original is " << orig << ", copy is " << copy << endl;
MyString copy2; // makes an empty string
copy2 = orig; // invoke operator=
copy2[0] = 'f'; // change first letter of the *copy*
cout << "original is " << orig << ", copy is " << copy2 << endl;
copy2 = "Copy Cat";
copy2 = copy2; // copy onto self and see what happens
cout << "after self assignment, copy is " << copy2 << endl;
cout << "Testing pass & return MyStrings by value and ref" << endl;
MyString val = "winky";
MyString sum = AppendTest("Boo", val);
cout << "after calling Append, sum is " << sum << endl;
cout << "val is " << val << endl;
val = sum;
cout << "after assign, val is " << val << endl;
}
MyString::MyString()
{
string = new char[0];
string[0] = 0;
}
MyString::MyString(cons char *inString)
{
string = new char[strlen(inString)+1];
strcpy(string,inString);
}
MyString::~MyString()
{
delete []string;
}
ostream& operator<<(ostream &out,cons MyString &outString)
{
out<<outString.string;
return out;
}
MyString MyString:: operator=(cons MyString right)
{
if (this != &right)
{
delete []string;
string = new char[strlen(right.string)+1];
strcpy(string,right.string);
}
return *this;
}
MyString::MyString(cons MyString &right)
{
string = new char[strlen(right.string)+1];
strcpy(string,right.string);
}
char& MyString::operator[](int index)
{
assert(index>=0 && index < strlen(string));
return string[index];
}
char MyString::operator[](int index)cons
{
assert(index>=0 && index < strlen(string));
return string[index];
}
istream& operator>>(istream& in,MyString &inString)
{
char temp[128];
delete [] inString.string;
in>>temp;
strcpy(inString.string,temp);
return in;
}
void MyString::read(istream &inString,char delimit)
{
char temp[128];
delete []string;
inString.getline(temp,127,delimit);
strcpy(string,temp);
}
MyString operator+(cons MyString left,cons MyString right)
{
MyString temp;
//temporary mystring to hold contents of left.string+right.string
temp.string = new char[strlen(left.string)+strlen(right.string)+1];
//dynamic array size of left.string+right.string+1
strcat(left.string,right.string);
//To make left.string+right.string into left.string
strcpy(temp.string,left.string);
//To copy the contents of left.string into temp.string;
return temp;
//To return the copy of MyString temp
}
MyString& MyString :: operator+=(cons MyString &right)
{
*this = *this+right;
return *this;
}
int MyString::length()cons
{
return strlen(string);
}
bool operator<(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) < 0;
}
bool operator<=(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) <= 1;
}
bool operator>(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) > 0;
}
bool operator>=(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) >= 1;
}
bool operator==(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) == 1;
}
bool operator!=(cons MyString &left, cons MyString &right)
{
return strcmp(left.string,right.string) != 1;
}
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