Handout 0

A Class Example

1. // Handout 0 - myClass.h
3. #ifndef MYCLASS_H
4. #define MYCLASS_H
6. class myClass {
7. public:
8. myClass(int); // constructor
9. ~myClass(); // destructor
10. void addToMyClass(int);
11. void subFromMyClass(int);
12. void showValue();
13. private:
14. int daValue;
15. };
17. #endif

1. // Handout 0 - myClass.cpp
3. // Implementation of the methods defined in myClass.h
5. #include <iostream.h>
6. #include "myClass.h"
8. // constructor
9. myClass::myClass(int x) {
10. daValue = x;
11. cout << "myClass Constructor called" << endl;
12. cout << "value of daValue is " << daValue << endl;
13. }
15. // destructor
16. myClass::~myClass() {
18. cout << "myClass Destructor called" << endl;
19. cout << "the value of daValue is " << daValue << endl;
20. }
22. void myClass::addToMyClass(int stuff_to_add) {
23. daValue += stuff_to_add;
24. }
26. void myClass::subFromMyClass(int stuff_to_subtract) {
27. myClass::addToMyClass(- stuff_to_subtract);
28. }
30. void myClass::showValue() {
31. cout << "the value of daValue is " << daValue << endl;
32. }
34. // Handout 0 Class Example - myProgram.cpp
36. #include <iostream.h>
37. #include "myClass.h"
39. int main() {
41. myClass this_one(1); // create one instance
42. myClass the_other_one(2); // create a second instance
44. this_one.addToMyClass(3);
45. this_one.subFromMyClass(2);
46. this_one.showValue();
48. the_other_one.addToMyClass(12);
49. the_other_one.subFromMyClass(22);
50. the_other_one.showValue();
52. return 0;
53. }

output from the program is as follows:

myClass Constructor called
value of daValue is 1
myClass Constructor called
value of daValue is 2
the value of daValue is 2
the value of daValue is -8
myClass Destructor called
the value of daValue is -8
myClass Destructor called
the value of daValue is 2