我打算写一个模板来生成随机数据的向量.问题是
std :: uniform_int_distribution只接受整数类型,而float类型的std :: uniform_real_distribution.我想把两者结合起来.这是我的代码.
std :: uniform_int_distribution只接受整数类型,而float类型的std :: uniform_real_distribution.我想把两者结合起来.这是我的代码.
#include <vector>
#include <random>
#include <algorithm>
#include <iterator>
#include <functional>
template<typename T>
std::vector<T> generate_vector(size_t N,T lower = T(0),T higher = T(99)) {
// Specify the engine and distribution.
if constexpr (std::is_integral<T>) {
std::uniform_int_distribution<T> distribution(lower,higher);
}
else if constexpr (std::is_floating_point<T>) {
std::uniform_real_distribution<T> distribution(lower,higher);
}
std::mt19937 engine; // Mersenne twister MT19937
auto generator = std::bind(distribution,engine);
std::vector<T> vec(N);
std::generate(vec.begin(),vec.end(),generator);
return vec;
我很困惑如何在if条件下实现语句.整数类型应包括：short,int,long,long long,unsigned short,unsigned int,unsigned long或unsigned long long.浮点类型包括float,double或long double.
任何帮助建议？
解决方法
在C17之前的编译器中,您可以使用模板特化来实现if-else逻辑.
// Declare a class template
template <bool is_integral,typename T> struct uniform_distribution_selector;
// Specialize for true
template <typename T> struct uniform_distribution_selector<true,T>
{
using type = typename std::uniform_int_distribution<T>;
};
// Specialize for false
template <typename T> struct uniform_distribution_selector<false,T>
{
using type = typename std::uniform_real_distribution<T>;
};
template<typename T>
std::vector<T> generate_vector(size_t N,T higher = T(99))
{
// Select the appropriate distribution type.
using uniform_distribution_type = typename uniform_distribution_selector<std::is_integral<T>::value,T>::type;
uniform_distribution_type distribution(lower,higher);
std::mt19937 engine;
auto generator = std::bind(distribution,engine);
std::vector<T> vec(N);
std::generate(vec.begin(),generator);
return vec;
}
