Utilizing STL Contiguous-Containers in a better way
A very effective way to store a large amount of heavy-weight objects inside contiguous-containers in C++.
Containers like Vector can’t store a large amount of heavy-weight objects. They can either store a few heavy objects or a large amount of light-weight objects. A simple workaround for this problem is to use to pointer-type objects.
For instance, if we store 3 integers inside a vector, this will cost us 12 bytes. Similarly, if we have stored 3 objects of 10,000 bytes, this will reserve a total of 30,000 bytes inside vector. If we continue to allocate these heavy objects, soon we’ll reach limit of that container and we’ll no longer be able to allocate new objects inside that container.
However, if we used pointer type to store these 3 objects inside the vector (using new keyword), this will only reserve 24 bytes inside vector (as each pointer costs us 8 bytes irrespective of type, so total 3x8=24 bytes), while additional 30,000 bytes in heap-memory. Now, we can easily store a large amount of these heavy-weight objects inside vector or any other contiguous-container.
This technique becomes very handy when you need to allocate heavy resources through contiguous-container in large-scale projects.
Note: Internally, vector allocates bytes by multiplying the size of object-type with total no. of objects.
P.S: If you have any ambiguity in understanding the concept, please watch this reference video. Peace!
