如何为const std :: vector释放内存<unsigned char>

Question

I am using one library api which returns const std::vector . Below is the code

const std::vector<unsigned char> myvar = getData();

Now i have cleanup memory for myvar. How to do this with c++.

I am trying something like

std::for_each(myvar.begin(), myvar.end(), [&](unsigned char mychar)
{
    cout<<mychar<<",";


    delete &mychar;

});

But failing with the heap curruption.

Thanks for the input.

Answer 1

STL uses RAII idiom, , it allocates memory when necessary and deallocate automatically.

You don't need to manually deallcoate myvar , just let myvar go out of scope, all memory will be deallocate automatically.

// new scope, maybe function, maybe if/while scope: 
{
    const std::vector<unsigned char> myvar = getData();
}
// myvar will be deallocated 

Note, always call new/delete , new [] / delete[] in pair, you didn't call new for any myvar member, you don't need call delete at all.

Answer 2

You do not have to manually delete the contents of that vector. The vector's destructor will take care of all necessary memory allocation, and will be called when the object goes out of scope. For example,

{

  const std::vector<unsigned char> v('a', 1000); // size 1000 vector

} // v's destructor called here.

This is one of the many reasons to use standard library types. Have a look at the not very aptly named resource acquisition is initialization, or RAII .

Answer 3

void myFunc()
{
    const std::vector<unsigned char> myvar = getData();

} // <----- Like this

Vector will take care of deallocating its own contents, when it is destroyed at the end of its containing scope. Remember, you don't need to delete , unless you new .