boost Circular_buffer 使用实例

boost库提供Circular_buffer 环形缓冲区（不支持多生产者多消费者），并且会覆盖写数据。

下面给一个使用实例：
 

#include <boost/circular_buffer.hpp>
#include <iostream>

int main()
{
	// Create a circular buffer with a capacity for 3 integers.
	boost::circular_buffer<int> cb(3);

	// Insert threee elements into the buffer.
	cb.push_back(1);
	cb.push_back(2);
	cb.push_back(3);

	int a = cb[0];  // a == 1
	int b = cb[1];  // b == 2
	int c = cb[2];  // c == 3

        std::cout << "a = " << a << ", b = " << b << ", c = " << c << std::endl;
	// The buffer is full now, so pushing subsequent
	// elements will overwrite the front-most elements.

	cb.push_back(4);  // Overwrite 1 with 4.
	cb.push_back(5);  // Overwrite 2 with 5.

	// The buffer now contains 3, 4 and 5.
	a = cb[0];  // a == 3
	b = cb[1];  // b == 4
	c = cb[2];  // c == 5

        std::cout << "a = " << a << ", b = " << b << ", c = " << c << std::endl;
	// Elements can be popped from either the front or the back.
	cb.pop_back();  // 5 is removed.
	cb.pop_front(); // 3 is removed.

	// Leaving only one element with value = 4.
	int d = cb[0];  // d == 4
        std::cout << "d = " << d << std::endl;
	return 0;
}

输出：

a = 1, b = 2, c = 3
a = 3, b = 4, c = 5
d = 4