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// FILE: mystring.h
// CLASS PROVIDED: string
// This is a simple version of the Standard Library string.
// It is part of the namespace main_savitch_4, from the textbook
// "Data Structures and Other Objects Using C++"
// by Michal Main and Walter Savitch
//
// CONSTRUCTOR for the string class:
// string(const char str[ ] = "") -- default argument is the empty string.
// Precondition: str is an ordinary null-terminated string.
// Postcondition: The string contains the sequence of chars from str.
//
// CONSTANT MEMBER FUNCTIONS for the string class:
// size_t length( ) const
// Postcondition: The return value is the number of characters in the
// string.
//
// char operator [ ](size_t position) const
// Precondition: position < length( ).
// Postcondition: The value returned is the character at the specified
// position of the string. A string's positions start from 0 at the start
// of the sequence and go up to length( )-1 at the right end.
//
// MODIFICATION MEMBER FUNCTIONS for the string class:
// void operator +=(const string& addend)
// Postcondition: addend has been catenated to the end of the string.
//
// void operator +=(const char addend[ ])
// Precondition: addend is an ordinary null-terminated string.
// Postcondition: addend has been catenated to the end of the string.
//
// void operator +=(char addend)
// Postcondition: The single character addend has been catenated to the
// end of the string.
//
// void reserve(size_t n)
// Postcondition: All functions will now work efficiently (without
// allocating new memory) until n characters are in the string.
//
// NON-MEMBER FUNCTIONS for the string class:
// string operator +(const string& s1, const string& s2)
// Postcondition: The string returned is the catenation of s1 and s2.
//
// istream& operator >>(istream& ins, string& target)
// Postcondition: A string has been read from the istream ins, and the
// istream ins is then returned by the function. The reading operation
// skips white space (i.e., blanks, newlines, tabs) at the start of ins.
// Then the string is read up to the next white space or the end of the
// file. The white space character that terminates the string has not
// been read.
//
// ostream& operator <<(ostream& outs, const string& source)
// Postcondition: The sequence of characters in source has been written
// to outs. The return value is the ostream outs.
//
// void getline(istream& ins, string& target, char delimiter)
// Postcondition: A string has been read from the istream ins. The reading
// operation starts by skipping any white space, then reading all characters
// (including white space) until the delimiter is read and discarded (but
// not added to the end of the string). The return value is ins.
//
// VALUE SEMANTICS for the string class:
// Assignments and the copy constructor may be used with string objects.
//
// TOTAL ORDER SEMANTICS for the string class:
// The six comparison operators (==, !=, >=, <=, >, and <) are implemented
// for the string class, forming a total order semantics, using the usual
// lexicographic order on strings.
//
// DYNAMIC MEMORY usage by the string class:
// If there is insufficient dynamic memory then the following functions call
// new_handler: The constructors, resize, operator +=, operator +, and the
// assignment operator.
#ifndef MAIN_SAVITCH_CHAPTER4_MYSTRING_H
#define MAIN_SAVITCH_CHAPTER4_MYSTRING_H
#include <cstdlib> // Provides size_t
namespace main_savitch_4
{
class string
{
public:
// CONSTRUCTORS and DESTRUCTOR
string(const char str[ ] = "");
string(const string& source);
~string( );
// MODIFICATION MEMBER FUNCTIONS
void operator +=(const string& addend);
void operator +=(const char addend[ ]);
void operator +=(char addend);
void reserve(size_t n);
void operator =(const string& source);
// CONSTANT MEMBER FUNCTIONS
size_t length( ) const { return current_length; }
char operator [ ](size_t position) const;
// FRIEND FUNCTIONS
friend ostream& operator <<(ostream& outs, const string& source);
friend bool operator ==(const string& s1, const string& s2);
friend bool operator !=(const string& s1, const string& s2);
friend bool operator >=(const string& s1, const string& s2);
friend bool operator <=(const string& s1, const string& s2);
friend bool operator > (const string& s1, const string& s2);
friend bool operator < (const string& s1, const string& s2);
private:
char *sequence;
size_t allocated;
size_t current_length;
};
// NON-MEMBER FUNCTIONS for the string class
string operator +(const string& s1, const string& s2);
istream& operator >>(istream& ins, string& target);
void getline(istream& ins, string& target, char delimiter);
}
#endif
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