char *p;
p = new char [50];
p = "hello";
cout << p << endl; // this successfully outputs word hello
delete[] p; // when this line is commented, program works but im sure there is a memory leak
dynamically deleting arrays
Author
This code gives me a core dump, something is wrong with the way I delete the memory. What am I doing wrong ?
edit: Put the code into a codebox
When you do p = "hello" you're actually changing what p is pointing to. In this example, you're pointing to the string "hello" rather than modifying the memory you allocated. You could try something like: strcpy(p, "hello") instead. That way, you'd be modifying your dynamically-allocated memory rather than making p point to a constant string.
Quote:Original post by GameDev135
This code gives me a core dump, something is wrong with the way I delete the memory. What am I doing wrong ?
*** Source Snippet Removed ***
edit: Put the code into a codebox
p = "hello";
It loses the dynamically allocated memory.
> p = "hello";
You have a mem leak here because you are assigning new address here to p pointer. You must first free array memory.
You have a mem leak here because you are assigning new address here to p pointer. You must first free array memory.
guys, i think he's/she's only just started on pointers :)
i'll try to teach ya about pointers real quick..
when you do this: p = new char[50] you're returned a memory address, eg. 0x01 (just an example, its not really like this). this block of memory is 50 chars long, and p only points to the block, kinda like how a sign points to a town (ie, the sign is not the town!)
when you assign p like how you did, you "moved the sign". eg, when you do this: p = "hello", p now points to a new memory block (the memory block thats storing your string "hello") like 0x05.
the problem is, when you assigned p to "hello" you it no longer points to that originally allocated block (0x01), when you try to delete [] p, you're trying to delete memory that you didn't allocate yourself. you should be deleting 0x01, but p is pointing to 0x05, which isn't yours!
doing this is a no no!
hope that helped dude(or dudette)
-Danu
i'll try to teach ya about pointers real quick..
when you do this: p = new char[50] you're returned a memory address, eg. 0x01 (just an example, its not really like this). this block of memory is 50 chars long, and p only points to the block, kinda like how a sign points to a town (ie, the sign is not the town!)
when you assign p like how you did, you "moved the sign". eg, when you do this: p = "hello", p now points to a new memory block (the memory block thats storing your string "hello") like 0x05.
the problem is, when you assigned p to "hello" you it no longer points to that originally allocated block (0x01), when you try to delete [] p, you're trying to delete memory that you didn't allocate yourself. you should be deleting 0x01, but p is pointing to 0x05, which isn't yours!
doing this is a no no!
hope that helped dude(or dudette)
-Danu
Also when you should be aware that when you assign a string like
cheers
sam
p = "hello";cheers
sam
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