問(wèn)題描述
您能否解釋一下來(lái)自 HashMap 構(gòu)造函數(shù) 特別是這一行
Can you please explain this code snippet from HashMap constructor specifically the line
容量<<= 1:
capacity <<= 1:
// Find a power of 2 >= initialCapacity
198 int capacity = 1;
199 while (capacity < initialCapacity)
200 capacity <<= 1;
推薦答案
相當(dāng)于capacity = capacity <<<1;.
該操作將容量的位向左移動(dòng)一位，相當(dāng)于乘以 2.
It is equivalent to capacity = capacity << 1;.
That operation shifts capacity's bits one position to the left, which is equivalent to multiplying by 2.
您發(fā)布的特定代碼找到大于 initialCapacity 的 2 的最小冪.
The specific code you posted finds the smallest power of 2 which is larger than initialCapacity.
所以如果 initialCapacity 為 27，例如 capacity 在循環(huán)后將是 32 (2^5).
So if initialCapacity is 27, for example, capacity will be 32 (2^5) after the loop.
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