No, it doesn’t. The capacity of a vector never decreases. That isn’t mandated by the standard but it’s so both in standard library implementations of VC++ and g++. In order to set the capacity just enough to fit the size, use the famous swap trick vector<T>().swap(foo); In C++11 standard, you can do it more explicitly: … Read more
Matt Gallagher has written a pretty informative article on Cocoa’s collection classes, along with a couple of benchmarks (with & without initWithCapacity:, as well as cross class comparisons) http://cocoawithlove.com/2008/08/nsarray-or-nsset-nsdictionary-or.html His test (source available) for an NSMutableArray of length 1,000,000 took 0.582256sec without capacity and just 0.572139sec with capacity. Test | Time [NSMutableArray array] | 0.582256 … Read more
You may be able to get an approximate idea by using the JSON methods to turn the whole localStorage object to a JSON string: JSON.stringify(localStorage).length I don’t know how byte-accurate it would be, especially with the few bytes of added markup if you’re using additional objects – but I figure it’s better than thinking you’re … Read more
If you know in advance what the size of the ArrayList is going to be, it is more efficient to specify the initial capacity. If you don’t do this, the internal array will have to be repeatedly reallocated as the list grows. The larger the final list, the more time you save by avoiding the … Read more