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  1. PO
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    <p>I would use an array of T, a head and tail pointer, and add and get methods.</p> <p>Like: (Bug hunting is left to the user)</p> <pre><code>// Hijack these for simplicity import java.nio.BufferOverflowException; import java.nio.BufferUnderflowException; public class CircularBuffer&lt;T&gt; { private T[] buffer; private int tail; private int head; @SuppressWarnings("unchecked") public CircularBuffer(int n) { buffer = (T[]) new Object[n]; tail = 0; head = 0; } public void add(T toAdd) { if (head != (tail - 1)) { buffer[head++] = toAdd; } else { throw new BufferOverflowException(); } head = head % buffer.length; } public T get() { T t = null; int adjTail = tail &gt; head ? tail - buffer.length : tail; if (adjTail &lt; head) { t = (T) buffer[tail++]; tail = tail % buffer.length; } else { throw new BufferUnderflowException(); } return t; } public String toString() { return "CircularBuffer(size=" + buffer.length + ", head=" + head + ", tail=" + tail + ")"; } public static void main(String[] args) { CircularBuffer&lt;String&gt; b = new CircularBuffer&lt;String&gt;(3); for (int i = 0; i &lt; 10; i++) { System.out.println("Start: " + b); b.add("One"); System.out.println("One: " + b); b.add("Two"); System.out.println("Two: " + b); System.out.println("Got '" + b.get() + "', now " + b); b.add("Three"); System.out.println("Three: " + b); // Test Overflow // b.add("Four"); // System.out.println("Four: " + b); System.out.println("Got '" + b.get() + "', now " + b); System.out.println("Got '" + b.get() + "', now " + b); // Test Underflow // System.out.println("Got '" + b.get() + "', now " + b); // Back to start, let's shift on one b.add("Foo"); b.get(); } } } </code></pre>
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    1. POHow would you code an efficient Circular Buffer in Java or C#
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    1. USJeeBee
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    1. POHow would you code an efficient Circular Buffer in Java or C#
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    1. COOne bug found: The get() method does not set the elements of the internal array to `null` after the elements are removed from it, so there is a slight memory leak.
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      1. USEsko Luontola
    2. COYes, correct. :) I should have noticed that - my fault for not printing the elements in the list in the test code. Not as big as the bug of not using a standard API class or that in many use cases the thread-safe producer/consumer queue is more sensible ...
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    3. COWhy write "buffer = (T[]) new Object[n];" and not simply "buffer = new T[n];"? The cast in "t = (T) buffer[tail++];" also looks unnecessary to me. Or is this some Java peculiarity that I'm overlooking...?
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