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[C++] array of objects problem

Started by martinuk Mar 27, 2009 at 10:22 AM 7 replies 1.3k views

Original Post

Mar 27, 2009 at 10:22 AM

I have a program use an array of objects,say Banana b[100]; the program runs fine. if I create the banana object array in this way:


Banana b[100];

for(int i =0;i<100;i++)
{
   b.setValue(weight,color);
}

however, when i change to the following way, it has problem.


Banana* b[100];
for(int i =0;i<100;i++)
{
   b = new Banana(weight,color);
}

the b[0] or b[1] object is randomly destroyed for some reason. any idea why?

ToohrVyk

238

ToohrVyk

Mar 27, 2009 at 10:24 AM

What do you mean by "gets randomly destroyed" ? When does it happen, and how do you notice it happens ?

Evil Steve

382

Evil Steve

Mar 27, 2009 at 10:24 AM

How do you know it's randomly destroyed? The code you have there is perfectly fine, it must be some other problem.

martinuk

Author

martinuk

Mar 27, 2009 at 11:06 AM

In the real program, I loop through the array list and do some update

for example,
if i initialed all banana weight to 100g
and i loop through then and add 1 to the weight, for 100 times
thereafter all banana->weight should be 200g
but, sometimes later the banana[0]->weight become to 987679886 some random value.

it's a quite large program, here i just use banana[100] as an example.

if both way creating array objects are perfectly fine and with no security issue then, there must be other problems in the rest of my code.

SiCrane

Mod

473

SiCrane

Mar 27, 2009 at 11:08 AM

It sounds like you have a buffer overflow or bad pointer error somewhere else in your code, probably accessing the variable or variables immediately before your bananas.

NotAYakk

Mar 27, 2009 at 12:52 PM

Or she is leaving the data on the stack and returning from a function, not realising that the stack then gets overwritten.

martinuk

Author

martinuk

Apr 1, 2009 at 11:22 AM

better way doing it

Object** objArr;
objArr = new Object* [100]

maybe?

jpetrie

797

jpetrie

Apr 1, 2009 at 11:27 AM

Quote:

better way doing it

Object** objArr;
objArr = new Object* [100]

maybe?

Not really. There's nothing wrong with the code he posted that would be solved by dynamically allocating the array. The problem is elsewhere.

Zahlman

257

Zahlman

Apr 1, 2009 at 3:41 PM

Show the Banana class.

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