/* This file presents the interface for the String class, a class that stores character strings using run-time allocated arrays, while providing convenient operations to manipulate them. Written by: Joel C. Adams, Spring, 1993 at Calvin College. ------------------------------------------------------------*/ #ifndef STRINGS #define STRINGS #include #include class Strings { char // container for starting *String_; // address of the array int // the number of non-NUL Length_; // chars in the array public: // *** Constructors, Destructor, and Converters. /*--- Constructor to build a Strings object from a char-string constant. Pre: A Strings object has been declared, to be initialized with a character string constant. Recieve: Str, the char-string constant. Post: The Strings object has been constructed/initialized appropriately to store the char-string constant. -----------------------------------------------------------------------*/ Strings(const char Str[] = 0); /*--- Constructor to make a distinct copy of a Strings object. Pre: A copy of a Strings object is needed by the compiler. Receive: Str, the String to be copied. Post: This Strings object has been constructed/initialized as a copy of the original Strings object. -----------------------------------------------------------------------*/ Strings(const Strings& Str); /*--- Constructor to build a Strings object of a particular size. Pre: A Strings object has been declared, with an initialization character and with a given length. Receive: Ch, the initialization character, and Size, the length desired. Post: This Strings object has been constructed/initialized with its Length_ member set to Size, and its String_ member pointing to an array of Size chars, each element containing the value Ch. -----------------------------------------------------------------------*/ Strings(char Ch, unsigned Size = 1); /*--- Constructor to convert an int to a Strings object. Pre: A Strings object has been declared with an int as an argument. Receive: IntVal, an int value. Post: The object has been constructed and initialized as the Strings object equivalent to IntVal. -----------------------------------------------------------------------*/ Strings(int IntVal); /*--- Constructor to convert an double to a Strings object. Pre: A Strings object has been declared with a double as an argument. Receive: DoubleVal, an double value. Post: The object has been constructed and initialized as the Strings object equivalent to DoubleVal. -----------------------------------------------------------------------*/ Strings(double DoubleVal); /*--- Destructor to deallocate the memory of a Strings object. Pre: A Strings object's lifetime is over. Post: The dynamic memory of that object has been reclaimed. -----------------------------------------------------------------------*/ ~Strings(void); // string conversions /*--- This function converts a String of digits to a double value. Pre: This Strings object contains a sequence of digits. Return: The double value equivalent to those digits; 0.0 if the conversion cannot be performed. -----------------------------------------------------------------------*/ double Double(void); /*--- This function converts a String of digits to a long value. Pre: This Strings object contains a sequence of digits. Return: The long value equivalent to those digits; 0 if the conversion cannot be performed. -----------------------------------------------------------------------*/ long Long(void); /*--- This function converts a String of digits to an unsigned long value. Pre: This Strings object contains a sequence of digits. Return: The unsigned long value equivalent to those digits; 0 if the conversion cannot be performed. -----------------------------------------------------------------------*/ unsigned long Unsigned(void); /*--- This function converts a Strings object to the equivalent char- string whenever such a conversion is needed. Return: The char-string component of this Strings object. -----------------------------------------------------------------------*/ operator const char*() const { return String_; } // *** Operations /*--- Length returns the number of characters in a Strings object. Return: The number of characters in this object. -----------------------------------------------------------------------*/ int Length(void) const { return Length_; } /*--- Subscript: Retrieve the character with a given index. Receive: i, an index into this Strings object. Return: The (reference of the) char at index i. -----------------------------------------------------------------------*/ char& operator[] (unsigned i); char operator[] (unsigned i) const; /*--- Assignment to a Strings object. Receive: Str, a (reference to a) Strings object. Return: This Strings object as a copy of Str. -----------------------------------------------------------------------*/ Strings& operator= (const Strings& Str); /*--- Delete a portion of a Strings object. Receive: First, Last, two indices of this Strings object. Return: This Strings object without the characters from First..Last True, if and only if the operation is successful. -----------------------------------------------------------------------*/ int Delete(unsigned First, unsigned Last); /*--- Insert one Strings object into another Strings object. Receive: Str, a Strings object. Pos, an index within this Strings object. Return: This Strings object with the characters of Str inserted starting at index Pos. True, if and only if the operation is successful. -----------------------------------------------------------------------*/ int Insert(const Strings& Str, unsigned Pos); /*--- Replace a part of a Strings object with another Strings object. Receive: First, Last, two indices of this Strings object; Str, a Strings object. Return: This Strings object with its characters of First through Last replaced with those of Str. True, if and only if the operation is successful. -----------------------------------------------------------------------*/ int Replace(unsigned First, unsigned Last, const Strings& Str); /*--- Find the position of a substring within a Strings object. Receive: Str, a Strings object. Return: The index of the first occurrence of Str within this Strings object (-1 if it is not present). -----------------------------------------------------------------------*/ int Position(const Strings& Str) const; /*--- Concatenate two Strings objects. Receive: S1 and S2, two Strings objects. Return: The Strings object consisting of S1 and S2. -----------------------------------------------------------------------*/ friend Strings operator& (const Strings& S1, const Strings& S2); /*--- Retrieve a substring of a Strings object. Receive: First, Last, two indices of this Strings object. Return: The substring of this Strings object that begins at index First and ends at index Last. -----------------------------------------------------------------------*/ Strings operator() (unsigned First, unsigned Last); //--- Relational operators for Strings objects friend int operator== (const Strings& S1, const Strings& S2); friend int operator!= (const Strings& S1, const Strings& S2); friend int operator< (const Strings& S1, const Strings& S2); friend int operator> (const Strings& S1, const Strings& S2); friend int operator<= (const Strings& S1, const Strings& S2); friend int operator>= (const Strings& S1, const Strings& S2); //--- Relational operators for a String and a char-string friend int operator== (const Strings& S1, const char * S2); friend int operator!= (const Strings& S1, const char * S2); friend int operator< (const Strings& S1, const char * S2); friend int operator> (const Strings& S1, const char * S2); friend int operator<= (const Strings& S1, const char * S2); friend int operator>= (const Strings& S1, const char * S2); //--- Relational operators for a char-string and a String friend int operator== (const char * S1, const Strings& S2); friend int operator!= (const char * S1, const Strings& S2); friend int operator< (const char * S1, const Strings& S2); friend int operator> (const char * S1, const Strings& S2); friend int operator<= (const char * S1, const Strings& S2); friend int operator>= (const char * S1, const Strings& S2); // *** I/O friend ostream& operator<< (ostream& OutStream, const Strings& S); friend istream& operator>> (istream& InStream, Strings& S); // Bound on the number of chars that can be read ... enum {MaxLength = 1024}; /*--- Operation to get a line of input from the keyboard or a file. Receive: InStream, the stream (i or f) being read from; MaxChars, a bound on the number of chars to be read (default Strings::MaxLength); UntilChar, a char that halts the operation when it is read (default newline). Return: This Strings object, filled with either the next MaxChars characters from InStream, or all unread characters up to UntilChar in InStream, whichever is fewer. -----------------------------------------------------------------------*/ istream& GetLine(istream& InStream, unsigned MaxChars = Strings::MaxLength, char UntilChar = '\n'); }; #endif