我收到错误：
../ ConcreteRequest.h:23:49：错误：传递'const std :: map，std :: basic_string＆gt;'as'this' 'std :: map＆lt; _Key，_Tp，_Compare，_ Alloc＆gt; :: mapped_type＆amp;的参数 std :: map＆lt; _Key，_Tp，_Compare，_ Alloc＆gt; :: operator []（std :: map＆lt; _Key，_Tp， _Compare，_Alloc＆gt; :: key_type＆amp;＆amp;）[with _Key = std :: basic_string; _Tp = std :: basic_string; _Compare = std :: less＆gt ;; _Alloc = 的std ::分配器， std :: basic_string＆gt;取代; std :: map＆lt; _Key，_Tp，_Compare， _Alloc＆gt; :: mapped_type = std :: basic_string; std :: map＆lt; _Key，_Tp，_Compare，_Alloc＆gt; :: key_type = std :: basic_string]'丢弃限定符[-fpermissive]
#ifndef CONCRETEREQUEST_H
#define CONCRETEREQUEST_H
#include "RequestFactory.h"
#include "Request.h"
#include "MasterFile.h"
#include <map>
#include <string>
#include <iostream>
class ConcreteRequest : public RequestFactory
{
Request *createRequest(const std::map<std::string,std::string> &input) const
{
std::cout << "==Starting createRequest==" << std::endl;
Request *pRequest;
if (input["dataset"] == "masterfile")
{
pRequest = new MasterFile(input);
}
std::cout << "==Finishing createRequest==" << std::endl;
return pRequest;
}
};
#endif
这是if比较。为什么呢？