#include <iostream>
#include <type_traits>

template<typename T>
void IsFloat()
{
    if(std::is_floating_point<T>::value)
    {
        std::cout << "Type " << typeid(T).name() << " is a floating point type." << std::endl;
    }
    else
    {
        std::cout << "Type " << typeid(T).name() << " is not a floating point type." << std::endl;
    }
}

int main()
{
    IsFloat<double>();
    IsFloat<int>();
    IsFloat<float>();
}

Type double is a floating point type.
Type int is not a floating point type.
Type float is a floating point type.

#include <iostream>
#include <type_traits>

template<typename T>
typename std::enable_if<std::is_floating_point<T>::value, T>::type
Add(T a, T b)
{
    return a + b;
}

int main()
{
    std::cout << Add(3.5, 4.2) << std::endl; // 输出7.7
    std::cout << Add(5, 6) << std::endl; // 编译错误，因为类型int不是浮点类型
}

#include <iostream>
#include <type_traits>

template<size_t N, typename T>
class ArrayHelper
{
public:
    static typename std::enable_if<std::is_floating_point<T>::value, T>::type
    Sum(T (&arr)[N])
    {
        T sum = 0.0;
        for (size_t i = 0; i < N; ++i)
        {
            sum += arr[i];
        }
        return sum;
    }
};

int main()
{
    double floatArray[] = {1.1, 2.2, 3.3, 4.4, 5.5};
    int intArray[] = {1, 2, 3, 4, 5};

    std::cout << "Sum of float array: " << ArrayHelper<5, double>::Sum(floatArray) << std::endl;
    std::cout << "Sum of int array: " << ArrayHelper<5, int>::Sum(intArray) << std::endl;
}

Sum of float array: 16.5
Sum of int array: 15