STL map error: no template named 'map' in namespace 'std'; did you mean 'max'?

Question

I am working on an application that tracks the frequency of letters in a string. To do this I created the following Struct

struct MessageLetter{
  char letter;
  int count;
  MessageLetter(char letter, int freq)
  : letter(letter), count(freq)
  {}
};

Now I am trying to create a stl::map like follows...

  std::map<std::string, MessageLetter> lList;
  for(int i = 0; i < output.length(); i++){
    std::cout << i << output[i] << std::endl;
    if(lList.find(output[i]) == lList.end()){
      std::cout << "Letter not found" << std::endl;
      MessageLetter m = {output[i],1};
      lList[output[i]] = m;
    }
    else{
      std::cout << "Letter found" << std::endl;
    }
  }

When I try to compile this I get the following...

test.cpp:95:8: error: no template named 'map' in namespace 'std'; did you mean 'max'?
  std::map<std::string, MessageLetter> lList;

I am new to c++ so any guidance would be great. And if this is a duplicate I will be happy to remove. Any other information (C++ version etc) will be provided if needed. This is eventually going to be a native Android app.

Answer 1

#include <map>

问题解决了。