c++ - 使用 unordered_map 时出现编译时错误

Question

我得到了下面的示例代码

// unordered_map::find
#include <iostream>
#include <string>
#include <unordered_map>

int main ()
{
  std::unordered_map<std::string,double> mymap = {
     {"mom",5.4},
     {"dad",6.1},
     {"bro",5.9} };

  std::string input;
  std::cout << "who? ";
  getline (std::cin,input);

  std::unordered_map<std::string,double>::const_iterator got = mymap.find (input);

  if ( got == mymap.end() )
    std::cout << "not found";
  else
    std::cout << got->first << " is " << got->second;

  std::cout << std::endl;

  return 0;

当我尝试在 Windows 7 上使用 VS 2010 编译它时，我得到编译时错误（虽然它看起来不错）

1>\testing.cpp(13): error C2552: 'mymap' : non-aggregates cannot be initialized with initializer list
1>          'std::tr1::unordered_map<_Kty,_Ty>' : Types with a base are not aggregate
1>          with
1>          [
1>              _Kty=std::string,
1>              _Ty=double
1>          ]
1>\testing.cpp(14): error C2078: too many initializers
1>\testing.cpp(15): fatal error C1903: unable to recover from previous error(s); stopping compilation

Answer 1

您的编译器 (VC10) 不支持统一初始化。您的程序在符合标准的编译器上编译得很好。