C++ 获取变量名称 & 获取类型的名称

怼烎@ 2022-08-18 11:55 997阅读 0赞

本文转载自：http://cherishlc.iteye.com/blog/1750013

1、获取变量名称

采用如下宏定义即可，这个宏定义将表达式x直接转换为对应的字符串：

#define varName(x) #x
    #define printExp(exp) cout<<#exp<<"为:\t\t"<<(exp)<<endl
    #define printExpToString(exp) cout<<(string(#exp)+"为:\t\t")<<(exp).toString()<<endl //注意exp加括号更安全

用法：

out<<varName(aInt)<<endl; \\输出为：  aInt

2、获取类型名称    
采用如下宏定义即可，这个宏定义将表达式x直接转换为对应的字符串：

//可能需要#include <typeinfo>  好像不引用也成  
    cout<<typeid(int).name()<<endl;

更多的用法见最后的程序；   
先看一下输出：

![Center][]

3、完整的程序:

#include <string>
    #include <sstream>
    #include <iostream>
    using namespace std;
    
    #define varName(x) #x
    #define printExp(exp) cout<<#exp<<"为:\t\t"<<(exp)<<endl
    #define printExpToString(exp) cout<<(string(#exp)+"为:\t\t")<<(exp).toString()<<endl //注意exp加括号更安全
    
    namespace LC {
    	template<typename T> class Base {
    	public:
    		virtual string toString() {
    			stringstream ss;
    			ss << typeid(*this).name();
    			return ss.str();
    		}
    
    		Base operator+(int a) {
    			return *this;
    		}
    	};
    
    	template<typename T> class Derived : public Base<T> {
    	public:
    		virtual string toString() {
    			stringstream ss;
    			ss << typeid(*this).name();
    			return ss.str();
    		}
    	};
    }
    
    typedef LC::Base<double> BaseDouble;
    
    typedef LC::Derived<int> DerivedInt;
    
    int main(int argc, char** argv)
    {
    	int aInt = 1;
    	printExp(aInt);
    	printExp(typeid(int).name());
    	printExp(typeid(aInt).name());
    	cout << "变量名称为：" << varName(aInt) << endl;
    
    	cout << endl;
    	BaseDouble base;
    	printExpToString(base);
    	printExpToString(base + 5 + 4);//若定义中exp不加括号就无法编译了
    	printExpToString((LC::Base<int>)DerivedInt());
    
    	cout << endl;
    	DerivedInt derived;
    	LC::Base<int>* pBase = &derived;
    	LC::Base<int> baseCast = derived;
    	printExpToString(*pBase);
    	printExpToString(derived);
    	printExpToString(baseCast);
    
    	printExp(typeid(*pBase) == typeid(derived));
    	printExp(typeid(baseCast) == typeid(derived));
    
    	system("pause");
    	return 0;
    }

[Center]: /images/20220731/fc6bd48fae7a48778f48d02e24ad7a73.png