Freeing memory

[c_weed]

I'm not very knowledgable about when memory leaks occure and how to prevent them.

I have a for(;; ) loop and inside there is a variable, that gets written over each itteration,

char** vecDat = new char *[vehichle.size() + 1];

At the bottom of the for loop I call

delete [] vecData;

Should I be doing anything else?

I was taught to delete[] when new [] had been used, otherwise use delete. But there's new *[] here so I'm not sure.

[MutantJohn]

Can you run your code through a leak checker like Valgrind?

[phantomotap]

O_o

Consider your question in the context of a `typedef': (Please, do not use such a `typedef' in real code.)

typedef char * type;
type * s = new type[c];
delete[] s;

That isn't different from what you've been told: you've used `new[]' so you need to use a `delete[]'.

Soma

[c_weed]

Can you run your code through a leak checker like Valgrind?

I've never heard of a leack checker. How does it work?

[Matticus]

I've never heard of a leack checker. How does it work?

Why ask when you can search?

Valgrind - Wikipedia, the free encyclopedia
Valgrind

One of the important skills in a programmers repertoire is searching out information. This was an easy one.

[Elysia]

I'm not very knowledgable about when memory leaks occure and how to prevent them.

Use smart pointers. Use standard library containers. What you've shown can be easy be done with a vector at 0 risk for forgetting to free memory. There really shouldn't be that much raw new and delete in a good codebase.

[MutantJohn]

Use smart pointers. Use standard library containers. What you've shown can be easy be done with a vector at 0 risk for forgetting to free memory. There really shouldn't be that much raw new and delete in a good codebase.

I feel like this sidesteps the OP's main concerns.

@OP

I think this would help the most : Memory leak - Wikipedia, the free encyclopedia

And if you're on Linux, Valgrind is indispensable. Windows programmers just write leaky code is all.

Oh wait, I just googled it and I found this : c - Is there a good Valgrind substitute for Windows? - Stack Overflow

Valgrind is a lot of things in one and I hope that link can help you find some useful tools. What Elysia said is smart but for the sake of understanding and education, I hope this info can help too.

[Elysia]

I feel like this sidesteps the OP's main concerns.

I don't see how since the concerns seemed already addressed anyway. Besides, you don't write code like the OP's in today's C++, so the example is outright wrong.

[MutantJohn]

I will admit, this example is very confusing to the eye. But prior to my post, I don't think anyone had answered the OP's questions about what a leak is specifically and what causes it. Granted, all I did was link to wiki and then stack overflow so that's about that, I guess.

[antred]

By all means, you should follow Eylsia's advice and use RAII (RAII) to manage your resources. Avoid doing it manually where ever possible. But to get back to your potential leak. If you still suspect that you have a leak, it is not in the code you've shown us. However, since vecData is an array of char pointers, maybe you're also doing something like this in your code:

for ( std::size_t i = 0; i < vehichle.size() + 1; ++i )
{
    vecDat[ i ] = new char[ 100 ];
}

If so, then in addition to delete[]-ing your vecDat array, you obviously must also delete the various "sub-arrays" when you're done with them:

for ( std::size_t i = 0; i < vehichle.size() + 1; ++i )
{
    delete [] vecDat[ i ];
}

[c99tutorial]

At the bottom of the for loop I call

delete [] vecData;

Should I be doing anything else?

You should probably use unique_ptr, which is meant for this case. Example here std::unique_ptr - cppreference.com

[Elysia]

You should probably use unique_ptr, which is meant for this case. Example here std::unique_ptr - cppreference.com

No, in this case, a vector is more suitable, as has been mentioned earlier.