1. Constructors/Destructors Functions Revisited
Powerpoint 7
Constructors/Destructors Functions Revisited

2. Constructors C++ Has no return value May have parameters
Called automatically when a class object is declared
C++ has default constructors that are called whenever a class is declared even if no function with the same name exists
Should be public (or protected)

3. C++ Does not have a return type Cannot have parameters
Called automatically when the class object is destroyed
Deactivates storage allocated to a class
Declared with a tilde (~)

4. Example of Constructor
class sum {
public:
sum();
private:
int sum1,sum2; };

5. C++ void main () { sum obj1; //constructor is called at this //time
cout<<“end of main”<<endl;
return; }

6. C++ Functions sum::sum () { sum1=0; sum2=10;
cout<<sum1<<“ “<<sum2<<endl; }

7. C++ Sample Functions
What is the output??

8. the answer
0 10
end of main

9. Example of Constructor withArguments
class sum {
public:
sum(int,int);
private:
int sum1,sum2; };

10. C++ void main () { sum obj1 (10,20); //constructor is
// called at this time
cout<<“end of main”<<endl;
return; }

11. C++ Functions sum::sum (int x,int y)) { sum1=x; sum2=y;
cout<<sum1<<“ sum1”;
cout<<sum2<<“ sum2”<<endl; }

12. C++ Sample Functions
What is the output??
10 sum1
20 sum2
end main

13. Destructor:
Also a function
Identified by a ~ preceding function name
Called automatically when a class object is destroyed
May not have arguments
Should be public (or protected)

14. public:
~sum ();
sum::~sum ( ) {
close (infile);
close (outfile); }