1. How Classes Work with Memory Diagram
CSCE 121

2. output identifier stack
int main() { Date w(7, 7, 2015); // constructor w.setDay(4); // mutator w.printDate(); }
identifier
stack

3. class Date { int month; int day; int year; public: // constructors Date(); Date(int month, int day, int year); // accessors and mutators int getMonth(); void setMonth(int month); int getDay(); void setDay(int Day); int getYear(); void setYear(int year); // methods void printDate(); };

4. output identifier stack
int main() { Date w(7, 7, 2015); // constructor w.setDay(4); // mutator w.printDate(); }
month
main
day w
year
identifier
stack

5. output identifier stack implicit parameter ‘this’
Date::Date(int month, int day, int year) : month(month), day(day), year(year) {}
implicit parameter ‘this’
year
2015
day 7
Identifier resolution
First look for local version from parameter or local variable
Second, prepend with ‘this->’ to associate with object and try again
Date
month 7
this
month 7
main
day 7 w
year
2015
identifier
stack

6. output identifier stack
int main() { Date w(7, 7, 2015); // constructor w.setDay(4); // mutator w.printDate(); }
year
2015
day 7
Date
month 7
this
month 7
main
day 7 w
year
2015
identifier
stack

7. output identifier stack
void Date::setDay(int day) { if (day>=1 && day<=31) { this->day = day; } else if (day < 1) { this->day = 1; else if (day > 31) { this->day = 31;
day 4
setDay
this
year
2015
day 7
Date
month 7
this
month 7
main
day 4 w 7
year
2015
identifier
stack

8. output identifier stack
int main() { Date w(7, 7, 2015); // constructor w.setDay(4); // mutator w.printDate(); }
day 4
setDay
this
year
2015
day 7
Date
month 7
this
month 7
main
day 4 w 7
year
2015
identifier
stack

9. output identifier stack Recall: Identifier resolution
void Date::printDate() { cout << month << "/" << day; cout << "/" << year << endl; }
3/25
/2019
Recall: Identifier resolution
First look for local version from parameter or local variable
Second, prepend with this-> to associate with object and try again
printDate
this
day 4
setDay
this
year
2015
day 7
Date
month 7
this
So body essentially becomes:
cout << this->month << "/" << this->day;
cout << "/" << this->year << endl;
month 7
main
day 7 4 w
year
2015
identifier
stack

10. output identifier stack
int main() { Date w(7, 7, 2015); // constructor w.setDay(4); // mutator w.printDate(); }
3/25
/2019
printDate
this
day 4
setDay
this
year
2015
day 7
Date
month 7
this
month 7
main
day 4 w 7
year
2015
identifier
stack