U++ learning notes - relaxation

Because the default constructed array does not allocate memory , So the relaxation is initially zero .GetSlack You can use this function to find out how much slack there is in the array . Before the container is reallocated , The maximum number of elements that the array can hold can be through Max Function to obtain .GetSlack amount to and Between Max Bad Num：

TArray<int32> SlackArray;
// SlackArray.GetSlack() == 0
// SlackArray.Num()      == 0
// SlackArray.Max()      == 0

SlackArray.Add(1);
// SlackArray.GetSlack() == 3
// SlackArray.Num()      == 1
// SlackArray.Max()      == 4

SlackArray.Add(2);
SlackArray.Add(3);
SlackArray.Add(4);
SlackArray.Add(5);
// SlackArray.GetSlack() == 17
// SlackArray.Num()      == 5
// SlackArray.Max()      == 22

The above is TArray Automatic expansion of

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There is one Reset And Empty Similar functions , Except if the current assignment has provided the requested slack, It will not free memory . however , If requested slack more , It will allocate more memory ：

SlackArray.Reset(0);
// SlackArray.GetSlack() == 3
// SlackArray.Num()      == 0
// SlackArray.Max()      == 3
SlackArray.Reset(10);
// SlackArray.GetSlack() == 10
// SlackArray.Num()      == 0
// SlackArray.Max()      == 10

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Last , You can use this function to delete all slack, The Shrink Function will adjust the allocated size to the minimum size required to accommodate the current element .Shrink It has no effect on the elements in the array ：

SlackArray.Add(5);
SlackArray.Add(10);
SlackArray.Add(15);
SlackArray.Add(20);
// SlackArray.GetSlack() == 6
// SlackArray.Num()      == 4
// SlackArray.Max()      == 10
SlackArray.Shrink();
// SlackArray.GetSlack() == 0
// SlackArray.Num()      == 4
// SlackArray.Max()      == 4