Can you please add Preconditions and Post conditions for the code below: main.cp
ID: 3697470 • Letter: C
Question
Can you please add Preconditions and Post conditions for the code below:
main.cpp
#include "mystring.h"
#include <fstream>
#include <cctype> // for toupper()
#include <string> // for strchr(), strstr(), etc.
#include <cassert>
#include <iostream>
using namespace std;
using namespace cs2b_mystring;
bool eof(istream& in);
void BasicTest();
void RelationTest();
void ConcatTest();
void CopyTest();
myString AppendTest(const myString& ref, myString val);
int main()
{
BasicTest();
RelationTest();
ConcatTest();
CopyTest();
return 0;
}
bool eof(istream& in)
{
char ch;
in >> ch;
in.putback(ch);
return !in;
}
void BasicTest()
{
myString s;
cout << "----- Testing basic String creation & printing" << endl;
const 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("data.txt");
if (!in.is_open()){
std::cerr<<"file open fialed"<<endl;
return;
}
assert(in);
while (in.peek() == '#'){
in.ignore(128, ' ');
}
in >> s;
while (in) {
cout << "Read string = " << s << endl;
in >> s;
}
in.close();
cout << endl << "----- now, line by line" << endl;
ifstream in2("data.txt");
assert(in2);
while (in2.peek() == '#'){
in2.ignore(128, ' ');
}
s.read(in2, ' ');
while (in2) {
cout << "Read string = " << s << endl;
s.read(in2, ' ');
}
cout << endl << "----- Testing access to characters (using const)" << endl;
const myString s1("abcdefghijklmnopqsrtuvwxyz");
cout << "Whole string is " << s1 << endl;
cout << "now char by char: ";
for (size_t i = 0; i < s1.length(); i++){
cout << s1[i];
}
cout << endl << "----- Testing access to characters (using non-const)" << endl;
myString s2("abcdefghijklmnopqsrtuvwxyz");
cout << "Start with " << s2;
for (size_t i = 0; i < s2.length(); i++){
s2[i] = toupper(s2[i]);
}
cout << " and convert to " << s2 << endl;
}
void RelationTest()
{
cout << " ----- Testing relational operators between myStrings ";
const 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");
const 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");
const 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 ";
const 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 * ";
const myString a("abcde");
const 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 ");
const char *v = "programming";
cout << u << " += " << v << " = ";
cout << (u += v) << endl;
}
myString AppendTest(const 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); // invoke 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.cpp
#include "myString.h"
#include <string.h>
#include <cassert>
namespace cs2b_mystring{
myString::myString(void)
:_raw(NULL)
{
}
myString::myString(const char *rawString)
{
construction(rawString);
}
myString::myString(const myString &other)
{
construction(other._raw);
}
void myString::construction(const char *src)
{
assert(src!=NULL);
size_t size = strlen(src)+1;
_raw = new char[size];
memcpy(_raw,src,size*sizeof(char));
}
ostream& operator<<(ostream &out, const myString &str)
{
size_t size = str.length();
for (size_t i=0; i<size; ++i){
cout<<str[i];
}
cout.flush();
//or use printf(...);
return out;
}
istream& operator>>(istream &in, myString &str)
{
char ch = in.peek();
//skip leading-space
while (!in.eof() && (ch == ' ' || ch == ' ')){
in.get();
ch = in.peek();
}
if (str.isValid()){
delete[]str._raw;
str._raw = NULL;
}
char readStr[127];
size_t count = 0;
while (!in.eof() && (ch != ' ' && ch != ' ') && count < 126){
in.get();
readStr[count++] = ch;
ch = in.peek();
}
str._raw = new char[count + 1];
memcpy(str._raw, readStr, sizeof(char)*count);
str._raw[count]='';
return in;
}
myString::~myString(void)
{
if (_raw != NULL){
delete[]_raw;
}
}
void myString::read(istream &in, int endOfCharh)
{
char readStr[127];
in.getline(readStr, 127, endOfCharh);
if (_raw != NULL){
delete[]_raw;
}
size_t len = strlen(readStr)+1;
_raw = new char[len];
memcpy(_raw,readStr,sizeof(char)*len);
}
char& myString::operator[](const size_t pos)
{
assert(length()>pos);
return _raw[pos];
}
const char& myString::operator[](const size_t pos) const
{
assert(length()>pos);
return _raw[pos];
}
bool myString::operator<(const myString &rhs)const
{
return (*this < rhs._raw);
}
bool myString::operator<(const char *rhs)const
{
if (!isValid() || !rhs){
return false;
}
return strcmp(_raw, rhs)<0;
}
bool myString::operator<=(const myString &rhs)const
{
return (*this <= rhs._raw);
}
bool myString::operator<=(const char *rhs)const
{
if (!isValid() || !rhs){
return false;
}
return strcmp(_raw, rhs)<=0;
}
bool myString::operator>(const myString &rhs)const
{
return !(*this <= rhs);
}
bool myString::operator>(const char *rhs)const
{
return !(*this <= rhs);
}
bool myString::operator>=(const myString &rhs)const
{
return !(*this < rhs);
}
bool myString::operator>=(const char *rhs)const
{
return !(*this < rhs);
}
bool myString::operator==(const myString &rhs)const
{
return (*this == rhs._raw);
}
bool myString::operator==(const char *rhs)const
{
if (!isValid() || !rhs){
return false;
}
return strcmp(_raw, rhs)==0;
}
bool myString::operator!=(const myString &rhs)const
{
return !(*this==rhs);
}
bool myString::operator!=(const char *rhs)const
{
return !(*this==rhs);
}
myString myString::operator+(const myString &rhs)const
{
return *this+rhs._raw;
}
myString myString::operator+(const char *rhs)const
{
size_t first = length();
size_t second = rhs ? strlen(rhs) : 0;
size_t totall = first+second+1;
myString newStr;
newStr._raw = new char[totall];
char *p = newStr._raw;
memcpy(p,_raw,first*sizeof(char));
memcpy(p+first,rhs,(second)*sizeof(char));
*(p+totall-1) = '';
return newStr;
}
myString operator+(const char* lhs,const myString &rhs)
{
myString str(lhs);
return str+rhs;
}
myString& myString::operator+=(const myString &rhs)
{
return *this+=rhs._raw;
}
myString& myString::operator+=(const char *rhs)
{
size_t first = length();
size_t second = rhs ? strlen(rhs) : 0;
size_t totall = first+second+1;
char *newStr = new char[totall];
memcpy(newStr, _raw, first*sizeof(char));
memcpy(newStr+first,rhs, second*sizeof(char));
*(newStr+totall-1) = '';
if (_raw != NULL){
delete[]_raw;
}
_raw = newStr;
return *this;
}
size_t myString::length()const
{
return _raw ? strlen(_raw) : 0;
}
bool myString::isValid() const
{
return _raw!=NULL;
}
myString& myString::operator=(const myString &rhs)
{
if (this->equal(rhs)){
return *this;
}
if (_raw != NULL){
delete[]_raw;
}
int len = rhs.length();
_raw = new char[len+1];
memcpy(_raw, rhs._raw, sizeof(char)*len);
_raw[len] = '';
return *this;
}
bool myString::equal(const myString &other)
{
return _raw == other._raw;
}
}
myString.h
#pragma once
#include <iostream>
using std::cout;
using std::cin;
using std::ostream;
using std::istream;
namespace cs2b_mystring{
class myString
{
public:
//construct empty
myString(void);
//constructed by c-string
myString(const char *rawString);
//deep-copy;
myString(const myString &other);
//operator=
myString& operator=(const myString &rhs);
//operator<<
friend ostream& operator<<(ostream &out, const myString &str);
//operator>>, skip leading spaces, and end by space,limit length = 127(contains end of sequence)
friend istream& operator>>(istream &in, myString &str);
//ready read readyToReadLength sizes from istream-in, and then return size of reading factly
//limit length = 127(contains end of sequence)
void read(istream &in, int endOfChar);
//operator[]
char& operator[](const size_t pos);
//operator[]const
const char& operator[](const size_t pos)const;
//relational operators
bool operator<(const myString &rhs)const;
bool operator<(const char *rhs)const;
bool operator<=(const myString &rhs)const;
bool operator<=(const char *rhs)const;
bool operator>(const myString &rhs)const;
bool operator>(const char *rhs)const;
bool operator>=(const myString &rhs)const;
bool operator>=(const char *rhs)const;
bool operator==(const myString &rhs)const;
bool operator==(const char *rhs)const;
bool operator!=(const myString &rhs)const;
bool operator!=(const char *rhs)const;
//friend functins of relational operators
friend bool operator<(const char* lhs, const myString &rhs){return !(rhs < lhs);}
friend bool operator<=(const char* lhs, const myString &rhs){return !(rhs <= lhs);}
friend bool operator>(const char* lhs, const myString &rhs){return !(rhs > lhs);}
friend bool operator>=(const char* lhs, const myString &rhs){return !(rhs >= lhs);}
friend bool operator==(const char* lhs, const myString &rhs){return (rhs == lhs);}
friend bool operator!=(const char* lhs, const myString &rhs){return rhs != lhs;}
//combine
myString operator+(const myString &rhs)const;
myString operator+(const char *rhs)const;
friend myString operator+(const char* lhs,const myString &rhs);
myString& operator+=(const myString &rhs);
myString& operator+=(const char *rhs);
~myString(void);
size_t length()const;
protected:
void construction(const char *src);
//by address of _raw
bool equal(const myString &other);
//return true if _raw is not equal NULL
bool isValid()const;
private:
char *_raw;
};
}
Explanation / Answer
main.cpp
#include "mystring.h"
#include <fstream>
#include <cctype> // for toupper()
#include <string>
#include <cassert>
#include <iostream>
using namespace std;
using namespace cs_myString;
bool eof(istream& in);
void BasicTest();
void RelationTest();
void ConcatTest();
void CopyTest();
myString AppendTest(const myString& ref, myString val);
string boolString(bool convertMe);
int main()
{
BasicTest();
RelationTest();
ConcatTest();
CopyTest();
}
bool eof(istream& in)
{
char ch;
in >> ch;
in.putback(ch);
return !in;
}
string boolString(bool convertMe) {
if (convertMe) {
return "true";
} else {
return "false";
}
}
void BasicTest()
{
myString s;
cout << "----- Testing basic String creation & printing" << endl;
const 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("mystring.txt");
assert(in);
while (in.peek() == '#'){
in.ignore(128, ' ');
}
in >> s;
while (in) {
cout << "Read string = " << s << endl;
in >> s;
}
in.close();
cout << endl << "----- now, line by line" << endl;
ifstream in2("mystring.txt");
assert(in2);
while (in2.peek() == '#'){
in2.ignore(128, ' ');
}
s.read(in2, ' ');
while (in2) {
cout << "Read string = " << s << endl;
s.read(in2, ' ');
}
cout << endl << "----- Testing access to characters (using const)" << endl;
const myString s1("abcdefghijklmnopqsrtuvwxyz");
cout << "Whole string is " << s1 << endl;
cout << "now char by char: ";
for (int i = 0; i < s1.length(); i++){
cout << s1[i];
}
cout << endl << "----- Testing access to characters (using non-const)" << endl;
myString s2("abcdefghijklmnopqsrtuvwxyz");
cout << "Start with " << s2;
for (int i = 0; i < s2.length(); i++){
s2[i] = toupper(s2[i]);
}
cout << " and convert to " << s2 << endl;
}
void RelationTest()
{
cout << " ----- Testing relational operators between myStrings ";
const 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? " << boolString(strs[i] < strs[i+1]) << endl;
cout << " Is left <= right? " << boolString(strs[i] <= strs[i+1]) << endl;
cout << " Is left > right? " << boolString(strs[i] > strs[i+1]) << endl;
cout << " Is left >= right? " << boolString(strs[i] >= strs[i+1]) << endl;
cout << " Does left == right? " << boolString(strs[i] == strs[i+1]) << endl;
cout << " Does left != right ? " << boolString(strs[i] != strs[i+1]) << endl;
}
cout << " ----- Testing relations between myStrings and char * ";
myString s("he");
const char *t = "hello";
cout << "Comparing " << s << " to " << t << endl;
cout << " Is left < right? " << boolString(s < t) << endl;
cout << " Is left <= right? " << boolString(s <= t) << endl;
cout << " Is left > right? " << boolString(s > t) << endl;
cout << " Is left >= right? " << boolString(s >= t) << endl;
cout << " Does left == right? " << boolString(s == t) << endl;
cout << " Does left != right ? " << boolString(s != t) << endl;
myString u("wackity");
const char *v = "why";
cout << "Comparing " << v << " to " << u << endl;
cout << " Is left < right? " << boolString(v < u) << endl;
cout << " Is left <= right? " << boolString(v <= u) << endl;
cout << " Is left > right? " << boolString(v > u) << endl;
cout << " Is left >= right? " << boolString(v >= u) << endl;
cout << " Does left == right? " << boolString(v == u) << endl;
cout << " Does left != right ? " << boolString(v != u) << endl;
}
void ConcatTest()
{
cout << " ----- Testing concatentation on myStrings ";
const 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 * ";
const myString a("abcde");
const 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]) << "and";
cout << s2[i] << endl;
}
cout << " ----- Testing shorthand concat/assign using char * ";
myString u("I love ");
const char *v = "programming";
cout << u << " += " << v << " = ";
cout << (u += v) << endl;
}
myString AppendTest(const 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); // invoke 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.cpp
#include<iostream>
#include <cassert>
#include "myString.h"
using namespace std;
namespace cs_myString {
myString::myString() {
desc = new char[1];
strcpy(desc, "");
}
myString::myString(const char *inDesc) {
desc = new char[strlen(inDesc) + 1];
strcpy(desc, inDesc);
}
myString::myString(const myString& right) {
desc = new char[strlen(right.desc) + 1];
strcpy(desc, right.desc);
}
myString::~myString() {
delete [] desc;
}
myString myString::operator=(const myString& right) {
if (this != &right) {
delete [] desc;
desc = new char[strlen(right.desc) + 1];
strcpy(desc, right.desc);
}
return *this;
}
bool operator==(const myString& left, const myString& right) {
return strcmp(left.desc, right.desc) == 0;
}
bool operator<(const myString& left, const myString& right) {
return strcmp(left.desc, right.desc) < 0;
}
bool operator!=(const myString& 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 myString& right) {
return left < right || left == right;
}
bool operator>=(const myString& left, const myString& right) {
return !(left < right);
}
int myString::length() const {
return (int) strlen(desc);
}
ostream& operator<<(ostream& out, const myString& source) {
out << source.desc;
return out;
}
char myString::operator[](int index) const {
assert(index >= 0 && index < strlen(desc));
return desc[index];
}
char& myString::operator[](int index) {
assert(index >= 0 && index < strlen(desc));
return desc[index];
}
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;
}
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);
}
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;
}
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;
}
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;
}
}
======================================
myString.h
#ifndef myString_H
#define myString_H
#include <iostream>
using namespace std;
namespace cs_myString {
class myString {
public:
//DEFAULT CONSTRUCTOR
myString();
//Preconditon: Takes no parameter and return nothing..not even void
//Postcondition: initialize data member-'desc' with memory of size 1 and copy empty string to it
//CONSTRUCTOR
myString(const char *inDesc);
//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
//COPY CONSTRUCTOR
myString(const myString& right);
//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
//DESTRUCTOR
~myString();
//Preconditon: an myString object exist with valid length
//Postcondition: myString object is destroyed
//ASSIGNMENT OPERATOR
myString operator=(const myString& right);
//Preconditon: Input argument contains address to myString object:-Right.
//Postcondition: object is copied with size accordingly with specified object reference given at input
// CONCAT/ASSIGNMENT OPERATOR
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 char *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
int length() const;
//Preconditon: length donot take any argument
//Postcondition: returns length of myString object
// OVERLOADING THE EXTRACTION OPERATOR
friend ostream& operator<<(ostream& out, const myString& source);
//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.
//OVERLOADED INSERTION OPERATOR
friend istream& operator>>(istream& in, 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'.
//OVERLOADED All SIX OF THE RELATIONAL OPERATOR (<, <=, >, >=, ==, !=)
friend bool operator<(const myString &Left, const myString &Right);
//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.
//READ FROM FILE
void read(istream& inString,char delim);
//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.
//CONCAT OPERATOR
friend const myString operator+(const myString &left, const myString &right);
//Precondition:- Input parameters contains reference to two myString object:- Left and Right.
//Postcondition: function return's addition of two myString objects.
// OVERLOADING THE SQUARE BRACKETS
char operator[](int index) const;
//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);
//Preconditon: Input argument contains value of index.
//Postcondition: Returns the index to myString specifying the char to that location.
private:
char *desc; //POINTER DATA MEMBER
};
}
#endif
======================================
mystring.txt
# This file has some strings that are used in the string test to check
# reading strings from files. The default overloaded >> of your string
# class should skip over any leading spaces and read characters into
# the string object, stopping at the first whitespace character (this is
# similar to the behavior of >> on char *). The read method of the
# string class is a little fancier. It allows client to restrict
# how many characters at max to read and what character to use as
# delimiter, so you can stop at newline instead of space, for example.
# Reading consumes the delimiting character, so the next read starts
# after that.
#
The first time we will
read individual words, next
we read whole lines
sample output:
----- Testing basic String creation & printing
string [0] = Wow
string [1] = C++ is neat!
string [2] =
string [3] = a-z
----- Now reading myStrings from file
----- first, word by word
Read string = The
Read string = first
Read string = time
Read string = we
Read string = will
Read string = read
Read string = individual
Read string = words,
Read string = next
Read string = we
Read string = read
Read string = whole
Read string = lines
----- now, line by line
Read string = The first time we will
Read string = read individual words, next
Read string = we read whole lines
----- Testing access to characters (using const)
Whole string is abcdefghijklmnopqsrtuvwxyz
now char by char: abcdefghijklmnopqsrtuvwxyz
----- Testing access to characters (using non-const)
Start with abcdefghijklmnopqsrtuvwxyz and convert to ABCDEFGHIJKLMNOPQSRTUVWXYZ
----- Testing relational operators between myStrings
Comparing app to apple
Is left < right? true
Is left <= right? true
Is left > right? false
Is left >= right? false
Does left == right? false
Does left != right ? true
Comparing apple to
Is left < right? false
Is left <= right? false
Is left > right? true
Is left >= right? true
Does left == right? false
Does left != right ? true
Comparing to Banana
Is left < right? true
Is left <= right? true
Is left > right? false
Is left >= right? false
Does left == right? false
Does left != right ? true
Comparing Banana to Banana
Is left < right? false
Is left <= right? true
Is left > right? false
Is left >= right? true
Does left == right? true
Does left != right ? false
----- Testing relations between myStrings and char *
Comparing he to hello
Is left < right? true
Is left <= right? true
Is left > right? false
Is left >= right? false
Does left == right? false
Does left != right ? true
Comparing why to wackity
Is left < right? false
Is left <= right? false
Is left > right? true
Is left >= right? true
Does left == right? false
Does left != right ? true
----- Testing concatentation on myStrings
outrageous + milk = outrageousmilk
milk + = milk
+ cow = cow
cow + bell = cowbell
----- Testing concatentation between myString and char *
abcde + XYZ = abcdeXYZ
XYZ + abcde = XYZabcde
----- Testing shorthand concat/assign on myStrings
who += what = whowhatandwhowhat
what += WHEN = whatWHENandwhatWHEN
WHEN += Where = WHENWhereandWHENWhere
Where += why = WherewhyandWherewhy
----- Testing shorthand concat/assign using char *
I love += programming = I love programming
----- Testing copy constructor and operator= on myStrings
original is cake, copy is fake