PROGRAM 12


//  FILE NAME:  PROG12.CPP     PROGRAMMER NAME:  ANTHONY F. ORTIZ
//  THIS PROGRAM DEMONSTRATES A STRING OBJECT.
#include 
#include 
#include "ourstr.h"
int main ()
{
    clrscr ();
    string a;
    string b = "123";
    cout << "ENTER A STRING: ";
    cin >> a;
    a = a + b + a;
    cout << endl << "A =           " << a << endl << endl;
    cout << "LENGTH OF A = " << a.length () << endl;
    return 0;
}

//  I DIDN'T WRITE OURSTR.H AND OURSTR.CPP.

//  FILENAME:  OURSTR.H
//  THIS PROGRAM DECLARES A CLASS CALLED STRING.
#ifndef ourstr_h
#define ourstr_h
#include 
class string
{
    public:
        string :: string ();
        //  POST:  STRING OBJECT IS SET TO DEFAULT NULL STRING AS IN STRING A.
        string :: string (const string & strobj);
        //  POST:  OBJECT IS COPIED DURING ARGUMENT/PARAMETER ASSOCIATIONS
        //         AND DURING A FUNCTION RETURN.  OBJECT IS ALSO INITIALIZED AS 
        //         STRING ANOTHERSTR(ASTR).
        string :: string (const char * inittext);
        //  POST:  OBJECT IS INITIALIZED USING CHAR* ARGUMENT WHEN CONSTRUCTED
        //         AS STRING ASTR ("HALL").
        string :: ~string ();
        //  POST:  DESTRUCTOR.
        void string :: toUpper ();
        //  POST:  THE STRING IS CONVERTED TO UPPER CASE.
        string & string :: operator = (const char * rightvalue);
        //  POST:  THE LVALUE STRING OBJECT STORES THE STRING LITERAL AND
        //         THE DYNAMIC LENGTH OF THE EXPRESSION TO THE RIGHT OF =
        //         AS IN S1 = "A STRING LITERAL".
        string & string :: operator = (const string & rightvalue);
        //  POST:  THE LVALUE STRING OBJECT STORES THE STRING LITERAL AND
        //         THE DYNAMIC LENGTH OF THE EXPRESSION TO THE RIGHT OF =
        //         AS IN S1 = S2.
        string & string :: operator += (const string & right);
        //  POST:  THE RIGHT STRING OBJECT IS APPENDED TO THE
        //         STRING OBJECT ON THE LEFT.
        char & string :: operator [] (int index);
        //  POST:  A REFERENCE TO ONE INDIVIDUAL CHARACTER IS RETURNED.
        //         THIS MAY BE APPLIED TO NON-CONST OBJECTS.
        const char & string :: operator [] (int index) const;
        //  POST:  THE DYNAMIC LENGTH OF THE STRING OBJECT IS RETURNED.
        unsigned int string :: length () const;
        //  POST:  THE CHARACTERS (CHAR *) OF THE STRING OBJECT ARE RETURNED.
        //         COULD USE AS ARG TO IFSTREAM INFILE(FILENAME.THECHARS()).
        char * string :: chars () const;
        //  POST:  THE CHARACTERS (CHAR *) OF THE STRING OBJECT ARE RETURNED.
        //         COULD USE AS ARG TO IFSTREAM INFILE(FILENAME.THECHARS()).
    private:
        int len;
        char * thechars;
};
ostream & operator << (ostream & os, const string & outputstring);
istream & operator >> (istream & is, string & inputstring);
string operator + (const string & left, const string &right);
string operator + (const string & left, const char * right);
string operator + (const char * left, const string & right);
int operator < (const string & left, const string & right);
int operator <= (const string & left, const string & right);
int operator > (const string & left, const string & right);
int operator >= (const string & left, const string & right);
int operator == (const string & left, const string & right);
int operator != (const string & left, const string & right);
#include "ourstr.cpp"
#endif

//  FILENAME:  OURSTR.CPP
//  THIS PROGRAM CONTAINS THE IMPLEMENTATION OF THE CLASS STRING.
#include 
#include 
#include 
#include 
string :: string ()
{
    len = 0;
    thechars = new char [1];
    thechars [0] = 0;
}
string :: string (const char * inittext)
{
    len = strlen (inittext);
    thechars = new char [len + 1];
    if (! thechars)
    {
        cout << "**ERROR** MEMORY EXAUSTED TRYING TO CREATE "
        << inittext << endl
        << "...PROGRAM TERMINATED..." << endl;
        exit (0);
    }
    strcpy (thechars, inittext);
}
string :: string (const string & source)
{
    len = source.len;
    thechars = new char [len + 1];
    if (! thechars)
    {
        cout << "**ERROR** MEMORY EXAUSTED TRYING TO CREATE "
        << source.thechars << endl
        << "...PROGRAM TERMINATED..." << endl;
        exit (0);
    }
    strcpy (thechars, source.thechars);
}
unsigned int string :: length () const
{
    return len;
}
char * string :: chars () const
{
    return thechars;
}
string :: ~string ()
{
    delete [] thechars;
}
void string :: toUpper ()
{
    int lastchar = length ();
    for (int j = 0; j <= lastchar - 1; j++)
        thechars [j] = toupper (thechars [j]);
}
string & string :: operator = (const string & rightvalue)
{
    if (this != &rightvalue)
    {
        delete thechars;
        len = rightvalue.len;
        thechars = new char [len + 1];
        strcpy (thechars, rightvalue.thechars);
    }
    return *this;
}
string & string :: operator = (const char * rightvalue)
{
    delete thechars;
    len = strlen (rightvalue);
    thechars = new char [len + 1];
    strcpy (thechars, rightvalue);
    return *this;
}
string & string :: operator += (const string & right)
{
    int combinedlength = this->len + right.len;
    char * temp = new char [combinedlength + 1];
    if (! temp)
    {
        cout << "**ERROR** MEMORY EXAUSTED TRYING TO CREATE "
        << right.thechars << endl;
        exit (0);
    }
    strcpy (temp, thechars);
    strcat (temp, right.thechars);
    delete thechars;
    thechars = temp;
    len = combinedlength;
    return *this;
}
char & string :: operator [] (int index)
{
    if ((index < 0) || (index >= len))
    {
        cout << "\n**ERROR** FOR STRING OBJECT '" << thechars
        << "', SUBSCRIPT [" << index << "] IS OUT OF RANGE. " << endl;
        cout << "SUBSCRIPT MUST BE IN THE RANGE OF 1.." << (len - 1) << endl;
        exit (0);
    }
    return thechars [index];
}
const char & string :: operator [] (int index) const
{
    if ((index < 0) || (index > len))
    {
        cout << "\n**ERROR** FOR STRING OBJECT '" << thechars
        << "', INDEX [" << index << "] IS OUT OF RANGE. " << endl;
        cout << "INDEX MUST BE IN THE RANGE OF 1.." << (len - 1) << endl;
        exit (0);
    }
    return thechars [index];
}
ostream & operator << (ostream & os, const string & outputstring)
{
    os << outputstring.chars ();
    return os;
}
istream & operator >> (istream & is, string & inputstring)
{
    char temp [128];
    is >> temp;
    inputstring = string (temp);
    return is;
}
string operator + (const string & left, const string & right)
{
    string temp (left);
    temp += right;
    return temp;
}
string operator + (const string & left, const char * right)
{
    string temp (left);
    temp += right;
    return temp;
}
string operator + (const char * left, const string & right)
{
    string temp;
    temp = left;
    temp += right;
    return temp;
}
int operator < (const string & left, const string & right)
{
    return (strcmp (left.chars (), right.chars ()) < 0);
}
int operator <= (const string & left, const string & right)
{
    return ! (strcmp (left.chars (), right.chars ()) > 0);
}
int operator > (const string & left, const string & right)
{
    return (strcmp (left.chars (), right.chars ()) > 0);
}
int operator >= (const string & left, const string & right)
{
    return ! (strcmp (left.chars (), right.chars ()) < 0);
}
int operator == (const string & left, const string & right)
{
    return (strcmp (left.chars (), right.chars ()) == 0);
}
int operator != (const string & left, const string & right)
{
    return (strcmp (left.chars (), right.chars ()) != 0);
}

//  OUTFILE:  PROG12.OUT

ENTER A STRING: anthony
                                                                                
A =           anthony123anthony
                                                                                
LENGTH OF A = 17




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