我正在尝试使用boost::random
库获取真正的随机值。这是我的代码:
#include <iostream>
#include <boost/random/uniform_real_distribution.hpp>
#include <boost/random/mersenne_twister.hpp>
boost::random::mt19937 eng = boost::random::mt19937();
boost::random::uniform_real_distribution<double> urd =
boost::random::uniform_real_distribution<double>(0,20);
for (int i = 0; i <= 100; i++)
std::cout << urd(eng) << std::endl;
但我得到0到20之间的整数。
我该怎么办?
我还试过另一个引擎:
#include <iostream>
#include <boost/random/uniform_real_distribution.hpp>
#include <boost/random/lagged_fibonacci.hpp>
boost::random::lagged_fibonacci607 eng = boost::random::lagged_fibonacci607();
boost::random::uniform_real_distribution<double> urd =
boost::random::uniform_real_distribution<double>(0,20);
for (int i = 0; i <= 100; i++)
std::cout << urd(eng) << std::endl;
但没有......(总是整数值)
答案 0 :(得分:3)
输出之前如何设置精度? std::cout.precision(15);
?
或使用:
std::cout.precision(std::numeric_limits<double>::digits10);
示例强>
#include <iostream>
#include <limits>
#include <boost/random/uniform_real_distribution.hpp>
#include <boost/random/mersenne_twister.hpp>
int main()
{
boost::random::mt19937 eng = boost::random::mt19937();
boost::random::uniform_real_distribution<double> urd =
boost::random::uniform_real_distribution<double>(0,20);
std::cout.precision(std::numeric_limits<double>::digits10);
for (int i = 0; i <= 100; i++)
{
std::cout << urd(eng) << std::endl;
}
}
std::cout
的默认精度设置为6
,因此它可以在不设置此项的情况下工作,但是......