如何获取 boost::any 变量的数据类型？

Question

我正在寻找检查 boost::any 数据类型的方法。如果我将一个 int 分配给 boost::any，例如：

boost::any num1 = 5;

然后使用 typeid(num1).name() ，我希望我的输出为“int”，以便将来可以在 if else 语句中使用它。但是由于某种原因，它一直给我这个作为数据类型：N5boost3anyE

#include <typeinfo>
#include <iostream>
#include <boost/any.hpp>
using namespace std;

int main()
{
    int     a;
    double  b;
    float   c;
    bool    d;
    int16_t e;
    int32_t f;


    cout << "     int: " << typeid(a).name() << endl;
    cout << "sizeof(): " << sizeof(a) << endl << endl;

    cout << "  double: " << typeid(b).name() << endl;
    cout << "sizeof(): " << sizeof(b) << endl << endl;

    cout << "   float: " << typeid(c).name() << endl;
    cout << "sizeof(): " << sizeof(c) << endl << endl;

    cout << "    bool: " << typeid(d).name() << endl;
    cout << "sizeof(): " << sizeof(d) << endl << endl;

    cout << " int16_t: " << typeid(e).name() << endl;
    cout << "sizeof(): " << sizeof(e) << endl << endl;

    cout << " int32_t: " << typeid(f).name() << endl;
    cout << "sizeof(): " << sizeof(f) << endl << endl;

    boost::any num1 = 5;
    cout << "typeid(num1).name(): " << typeid(num1).name() << endl;

    boost::any num2 = "dog";
    cout << "typeid(num2).name(): " << typeid(num2).name() << endl;

}

输出：

johns-Air:cpp jdoe$ ./main 
int: i
sizeof(): 4

double: d
sizeof(): 8

float: f
sizeof(): 4

    bool: b
sizeof(): 1

int16_t: s
sizeof(): 2

int32_t: i
sizeof(): 4

typeid(num1).name(): N5boost3anyE
typeid(num2).name(): N5boost3anyE

Answer 1

您需要使用 boost::any 的成员函数 type() 其中 returns 包含值 const std::type_info& 的

cout << "num1.type().name(): " << num1.type().name() << endl;

如何获取 boost::any 变量的数据类型？

How can I get the data type for boost::any variable?

c++

boost

types