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Aff@n
Guest
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 Posted: Mon Oct 16, 2006 6:51 am Post subject: Problem in the aggregation concept.(during deletion of the p |
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Dear Brothers,
i am facing a problem
class compactdisc
{
char title[20];/string a;
int capacity;
public:
compactdisc();
compactdisc(char [],int);
};
class cd_drive
{
int speed;
char manufact[20];
compactdisc *ptr;
public:
cd_drive();
cd_drive(char [], int ,compactdisc *);
~cd_drive();
};
cd_drive::cd_drive(char a[], int spd ,compactdisc * a);
{
int counter=0;
counter=strlen(a);
for(int i=0;i<counter;i++)
manufact[i]=a[i];
for(int j=counter;j<20;j++)
manufact[j]=0;
ptr=new compactdisc;
ptr=a;
}
***************************************************
cd_drive::~cd_drive()
{
// how can i write the destructor of this if i write this
statement it gives memory leakage
// what is the reason about this ..is the way of deletion is
incorrect or any thing else
delete ptr;
}
int main()
{
compactdisc c1("programming",700);
compactdisc *c2;
c2=new compactdisc;
cd_drive("microsoft",210,c2);
delete c2;
return 0;
}
Please explain ! and also if any suggestion to make the program
efficient ..
thanks
your Brother. |
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Ian Collins
Guest
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| Posted: Mon Oct 16, 2006 9:10 am Post subject: Re: Problem in the aggregation concept.(during deletion of t |
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|
Aff@n wrote:
I'm sure there are some sisters lurking here!
| Quote: | i am facing a problem
class compactdisc
It's common practice to capitalise the fist letter of a class name. |
| Quote: | {
char title[20];/string a;
|
I assume these should have been two lines? Also, why isn't title a
std::string?
| Quote: | int capacity;
public:
compactdisc();
compactdisc(char [],int);
|
Why not use const std::string& as the first parameter?
| Quote: | };
class cd_drive
{
int speed;
char manufact[20];
Again, why not a std::string? |
Not a good choice of name. If this class takes ownership of the
compactdisc object, consider using std::auto_ptr here.
| Quote: |
public:
cd_drive();
cd_drive(char [], int ,compactdisc *);
Again, why not use const std::string& as the first parameter? |
| Quote: | ~cd_drive();
};
cd_drive::cd_drive(char a[], int spd ,compactdisc * a);
{
int counter=0;
counter=strlen(a);
Prefer initialiser lists over assignment. |
| Quote: | for(int i=0;i<counter;i++)
manufact[i]=a[i];
for(int j=counter;j<20;j++)
manufact[j]=0;
|
If you had used std::string, these could have been part of the
initialiser list.
| Quote: | ptr=new compactdisc;
ptr=a;
|
Why have you done this? This leaks the compactdisc object you have just
created.
| Quote: |
}
***************************************************
cd_drive::~cd_drive()
{
// how can i write the destructor of this if i write this
statement it gives memory leakage
// what is the reason about this ..is the way of deletion is
incorrect or any thing else
delete ptr;
|
Not required if you use std::auto_ptr.
| Quote: | }
int main()
{
compactdisc c1("programming",700);
compactdisc *c2;
c2=new compactdisc;
|
Do these in one line.
| Quote: | cd_drive("microsoft",210,c2);
|
Syntax error, where's the variable name?
You have passed c2 into a cd_drive object that will delete it when it
goes out of scope, so you end up deleting the same object twice. Not a
good idea.
--
Ian Collins. |
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