1 // Fig. 6.13: time2.cpp 2 // Member-function definitions for class Time. 3 #include <iostream> Outline. 4 5 using std::cout; 6 7 #include <iomanip>

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1 CISC11 Introduction to Computer Science Dr. McCoy Lecture 20 November, Using Default Arguments with Constructors Constructors Can specify default arguments Default constructors Defaults all arguments OR Explicitly requires no arguments Can be invoked with no arguments Only one per class // Fig..: time2.h 2 // Declaration of class Time. 3 // Member functions defined in time2.cpp. 3 1 // Fig..13: time2.cpp 2 // Member-function definitions for class Time. // prevent multiple inclusions of header file #ifndef TIME2_H #define TIME2_H time2.h (1 of 1) using std::cout; #include <iomanip> time2.cpp (1 of 3) 9 // Time abstract data type definition Default constructor specifying class Time { all arguments. public: 13 Time( int = 0, int = 0, int = 0); // default constructor 1 void settime( int, int, int ); // set hour, minute, second 1 void printuniversal(); // print universal-time format 1 void printstandard(); // print standard-time format 1 1 private: 19 int hour; // 0-23 (2-hour clock format) 20 int minute; // int second; // using std::setfill; using std::setw; // include definition of class Time from time2.h 13 #include "time2.h" 1 Constructor calls settime 1 // Time constructor initializes each data member to zero; to validate passed (or default) 1 // ensures all Time objects start in a consistent state values. 1 Time::Time( int hr, int min, int sec ) 1 { 19 settime( hr, min, sec ); // validate and set time } // end Time constructor 23 }; // end class Time 2 2 #endif 23 // set new Time value using universal time, perform validity 2 // checks on the data values and set invalid values to zero 2 void Time::setTime( int h, int m, int s ) 2 { 2 hour = ( h >= 0 && h < 2 )? h : 0; 2 minute = ( m >= 0 && m < 0 )? m : 0; 29 second = ( s >= 0 && s < 0 )? s : 0; time2.cpp (2 of 3) 2 // print Time in standard format 3 void Time::printStandard() { cout << ( ( hour == 0 hour == )? : hour % ) << ":" << setfill( '0' ) << setw( 2 ) << minute << ":" << setw( 2 ) << second << ( hour <? " AM" : " PM" ); time2.cpp (3 of 3) } // end function settime 9 0 } // end function printstandard 33 // print Time in universal format 3 void Time::printUniversal() 3 { 3 cout << setfill( '0' ) << setw( 2 ) << hour << ":" 3 << setw( 2 ) << minute << ":" 3 << setw( 2 ) << second; 39 0 } // end function printuniversal 1 1

2 1 // Fig..1: fig0_1.cpp 2 // Demonstrating a default constructor for class Time. using std::cout; using std::endl; // include definition of class Time from time2.h 9 #include "time2.h" fig0_1.cpp (1 of 2) 2 cout << "\n\nhour specified; default minute and second:\n "; 2 t2.printuniversal(); // 02:00:00 2 cout << "\n "; 2 t2.printstandard(); // 2:00:00 AM cout << "\n\nhour and minute specified; default second:\n "; 31 t3.printuniversal(); // 21:3:00 cout << "\n "; 33 t3.printstandard(); // 9:3:00 PM fig0_1.cpp (2 of 2) int main() { 13 Time t1; // all arguments defaulted 1 Time t2( 2 ); // minute and second defaulted 1 Time t3( 21, 3 ); // second defaulted 1 Time t(, 2, 2 // all values specified ); 1 Time t( 2,, 99 ); // all bad values specified 1 19 cout << "Constructed with:\n\n" 20 << "all default arguments:\n "; 21 t1.printuniversal(); // 00:00:00 cout << "\n "; 23 t1.printstandard(); // :00:00 AM 2 Initialize Time objects using default arguments. Initialize Time object with invalid values; validity checking will set values to cout << "\n\nhour, minute, and second specified:\n "; 3 t.printuniversal(); // :2:2 3 cout << "\n "; 3 t.printstandard(); // :2:2 PM 39 t constructed with invalid 0 cout << "\n\nall invalid values specified:\n "; arguments; values set to 0. 1 t.printuniversal(); // 00:00:00 2 cout << "\n "; 3 t.printstandard(); // :00:00 AM cout << endl; return 0; // end main } Constructed with: all default arguments: 00:00:00 :00:00 AM hour specified; default minute and second: 02:00:00 2:00:00 AM hour and minute specified; default second: 21:3:00 9:3:00 PM hour, minute, and second specified: :2:2 :2:2 PM all invalid values specified: 00:00:00 :00:00 AM fig0_1.cpp output (1 of 1) 9.1 Using Set and Get Functions Set functions Perform validity checks before modifying private data Notify if invalid values Indicate with return values Get functions Query functions Control format of data returned 1 // Fig..1: time3.h 2 // Declaration of class Time. 3 // Member functions defined in time3.cpp // prevent multiple inclusions of header file #ifndef TIME3_H #define TIME3_H time3.h (1 of 2) 2 void printuniversal(); // output universal-time format 2 void printstandard(); // output standard-time format 2 2 private: 29 int hour; // 0-23 (2-hour clock format) 30 int minute; // int second; // 0-9 time3.h (2 of 2) 9 class Time { 33 }; // end clas Time public: Time( int = 0, int = 0, int = 0 ); // default constructor 13 1 // set functions 1 void settime( int, int, int ); // set hour, minute, second 1 void sethour( int ); // set hour 1 void setminute( int ); // set minute 1 void setsecond( int ); // set second // get functions 21 int gethour(); // return hour int getminute(); // return minute 23 int getsecond(); // return second Set functions. Get functions. 3 3 #endif 2 2

3 1 // Fig..19: time3.cpp 2 // Member-function definitions for Time class. using std::cout; #include <iomanip> 9 using std::setfill; using std::setw; // include definition of class Time from time3.h 13 #include "time3.h" 1 1 // constructor function to initialize private data; 1 // calls member function settime to set variables; 1 // default values are 0 (see class definition) 1 Time::Time( int hr, int min, int sec ) 19 { 20 settime( hr, min, sec ); 21 } // end Time constructor time3.cpp (1 of ) 13 2 // set hour, minute and second values 2 void Time::setTime( int h, int m, int s ) 2 { 2 sethour( h ); time3.cpp (2 of ) 2 setminute( m ); 29 setsecond( s ); 30 Call set functions to perform 31 } // end function settime validity checking. 33 // set hour value 3 void Time::setHour( int h ) 3 { 3 hour = ( h >= 0 && h < 2 )? h : 0; 3 3 } // end function sethour 39 Set functions perform validity 0 // set minute value checks before modifying data. 1 void Time::setMinute( int m ) 2 { 3 minute = ( m >= 0 && m < 0 )? m : 0; } // end function setminute 1 23 // set second value void Time::setSecond( int s ) 9 { 0 second = ( s >= 0 && s < 0 )? s : 0; 1 2 } // end function setsecond 3 // return hour value int Time::getHour() { return hour; 9 } // end function gethour 0 1 // return minute value 2 int Time::getMinute() 3 { return minute; } // end function getminute Set function performs validity checks before modifying data. Get functions allow client to read data. time3.cpp (3 of ) 1 // return second value 9 int Time::getSecond() 0 { 1 return second; 2 3 } // end function getsecond Get function allows client to read data. // print Time in universal format void Time::printUniversal() { cout << setfill( '0' ) << setw( 2 ) << hour << ":" 9 << setw( 2 ) << minute << ":" 0 << setw( 2 ) << second; 1 2 } // end function printuniversal 3 // print Time in standard format void Time::printStandard() { cout << ( ( hour == 0 hour == )? : hour % ) << ":" << setfill( '0' ) << setw( 2 ) << minute 9 << ":" << setw( 2 ) << second 90 << ( hour <? " AM" : " PM" ); time3.cpp ( of ) } // end function printstandard 1 // Fig..20: fig0_20.cpp 2 // Demonstrating the Time class set and get functions using std::cout; using std::endl; // include definition of class Time from time3.h 9 #include "time3.h" void incrementminutes( Time &, const int ); // prototype 13 int main() 1 { 1 Time t; // create Time object 1 1 // set time individual set functions using 1 t.sethour( 1 ); // set hour to valid value 19 t.setminute( 3 ); // set minute to valid value 20 t.setsecond( 2 ); // set second to valid value Invoke set functions to set valid values. fig0_20.cpp (1 of 3) 1 // use get functions to obtain hour, minute and second 23 cout << "Result of setting all valid values:\n" 2 << " Hour: " << t.gethour() Attempt to set invalid values 2 << " Minute: " << t.getminute() using set functions. fig0_20.cpp 2 << " Second: " << t.getsecond(); (2 of 3) 2 2 // set time using individual set functions 29 t.sethour( 23 ); // invalid hour set to 0 30 t.setminute( 3 ); // set minute to valid value 31 t.setsecond( 33 ); // invalid second set to 0 Invalid values result in setting data members to // display hour, minute and second after setting 3 // invalid hour and second values 3 cout << "\n\nresult of attempting to set invalid hour and" 3 << " second:\n Hour: " << t.gethour() Modify data members using 3 << " Minute: " << t.getminute() function settime. 3 << " Second: " << t.getsecond() << "\n\n"; 39 0 t.settime(,, 0 ); // set time 1 incrementminutes( t, 3 ); // increment t's minute by return 0; } // end main 3

4 // add specified number of minutes to a Time object void incrementminutes( Time &tt, const int count ) 9 { 0 cout << "Incrementing minute " << count 1 << " times:\nstart time: "; 2 tt.printstandard(); 3 for ( int i = 0; i < count; i++ ) { tt.setminute( ( tt.getminute() + 1 ) % 0 ); if ( tt.getminute() == 0 ) tt.sethour( ( tt.gethour() + 1 ) % 2); 9 0 cout << "\nminute + 1: "; 1 tt.printstandard(); fig0_20.cpp Using get functions (3 of to 3) read data and set functions to modify data. 19 Result of setting all valid values: Hour: 1 Minute: 3 Second: 2 Result of attempting to set invalid hour and second: Hour: 0 Minute: 3 Second: 0 Incrementing minute 3 times: Start time: ::00 AM Attempting to set data minute + 1: :9:00 AM minute + 1: :00:00 PM members with invalid values minute + 1: :01:00 PM results in error message and members set to 0. fig0_20.cpp output (1 of 1) } // end for cout << endl; } // end function incrementminutes.1 Default Memberwise Assignment Assigning objects Assignment operator (=) Can assign one object to another of same type Default: memberwise assignment Each right member assigned individually to left member Passing, returning objects Objects passed as function arguments Objects returned from functions Default: pass-by-value Copy of object passed, returned Copy constructor Copy original values into new object 21 1 // Fig..2: fig0_2.cpp 2 // Demonstrating that class objects can be assigned 3 // to each other using default memberwise assignment. #include <iostream> using std::cout; using std::endl; 9 // class Date definition class Date { public: 13 Date( int = 1, int = 1, int = 1990 ); // default constructor 1 void print(); 1 1 private: 1 int month; 1 int day; 19 int year; }; // end class Date fig0_2.cpp (1 of 3) 23 // Date constructor with no range checking 2 Date::Date( int m, int d, int y ) 2 { 2 month = m; 2 day = d; 2 year = y; } // end Date constructor 31 // print Date in the format mm-dd-yyyy 33 void Date::print() 3 { 3 cout << month << '-' << day << '-' << year; 3 3 } // end function print 3 39 int main() 0 { 1 Date date1(,, 2002 ); 2 Date date2; // date2 defaults to 1/1/1990 fig0_2.cpp (2 of 3) 23 cout << "date1 = "; date1.print(); cout << "\ndate2 = "; Default memberwise date2.print(); assignment assigns each 9 date2 = date1; member of date1 // default memberwise individually assignment to each member 0 1 cout << "\n\nafter of date2. default memberwise assignment, date2 = "; 2 date2.print(); 3 cout << endl; return 0; } // end main date1 = date2 = After default memberwise assignment, date2 = fig0_2.cpp (3 of 3) fig0_2.cpp output (1 of 1) 2 3

5 1.1 Introduction 2 Dynamic (Linked) Data Structures (Chapter 1) Fixed-size data structures Arrays, structs Dynamic data structures Grow and shrink as program runs Linked lists Insert/remove items anywhere Stacks Insert/remove from top of stack Queues Like a line, insert at back, remove from front Binary trees High-speed searching/sorting of data Self-Referential Classes Self-Referential Classes 2 Self-referential class Has pointer to object of same class Link together to form useful data structures Lists, stacks, queues, trees Terminated with NULL pointer 1 Sample code class Node { public: Node( int ); void setdata( int ); int getdata() const; void setnextptr( Node * ); const Node *getnextptr() const; private: int data; Node *nextptr; }; Data member and pointer NULL pointer (points to nothing) Pointer to object called a link nextptr points to a Node 1.3 Dynamic Memory Allocation and Data Structures Dynamic Memory Allocation and Data Structures 30 Dynamic memory allocation Obtain and release memory during program execution Create and remove nodes Operator new Takes type of object to create Returns pointer to newly created object Node *newptr = new Node( ); Returns bad_alloc if not enough memory is the node's object data Operator delete delete newptr; Deallocates memory allocated by new, calls destructor Memory returned to system, can be used in future newptr not deleted, only the space it points to

6 1. Linked Lists Linked Lists Linked list Collection of self-referential class objects (nodes) connected by pointers (links) Accessed using pointer to first node of list Subsequent nodes accessed using the links in each node Link in last node is null (zero) Indicates end of list Data stored dynamically Nodes created as necessary Node can have data of any type... H D Q 1. Linked Lists Linked Lists 3 Linked lists vs. arrays Arrays can become full Allocating "extra" space in array wasteful, may never be used Linked lists can grow/shrink as needed Linked lists only become full when system runs out of memory Linked lists can be maintained in sorted order Insert element at proper position Existing elements do not need to be moved Selected linked list operations Insert node at front Insert node at back Remove node from front Remove node from back In following illustrations List has and (a) is before, (b) is after Insert at front 3 Insert at back 3 a) a) newptr newptr b) b) newptr newptr = newptr If list empty, then = = newptr newptr->nextptr = ->nextptr = newptr = newptr If list empty, then = = newptr

7 a) Remove from front 3 Remove from back "Walk" list until get next-to-last node, until currentptr->nextptr = a) 3 b) b) currentptr tempptr = tempptr = ->next If there are no more nodes, = = 0 tempptr = tempptr = currentptr delete tempptr delete tempptr