“未定义参考”试图引用静态字段 [英] "Undefined reference" trying to reference an static field

问题描述

我的测试类有这个定义：

  #ifndef TEST_H 
 #define TEST_H 
 
 #include< iostream> 
 #include< cstdlib> 
 #include< ctime> 
 #include< fstream> 
 
 class Test {
 public：
 static bool testAll（bool debug = false）; 
 private：
 static bool testVector2D（bool debug = false）; 
 static bool testPolygon（bool debug = false）; 
 static bool testRectangle（bool debug = false）; 
 static bool testMap（bool debug = false）; 
 
 static std :: ofstream outStream; 
 static std :: ifstream inStream; 
 
 static void prepareWriting（）; 
 static void prepareReading（）; 
 
 const char tempFileName []; 
};当我尝试使用Test :: outStream或Test :: inStream时，例如：
  p> 
 
 
  void Test :: prepareWriting（）{
 if（Test :: inStream.is_open（））{
 Test :: inStream.close（）; 
} 
 Test :: outStream.open（testFileName，ios :: out）; 
} 
  
 
 
我得到这个msg：未定义的引用`Test :: inStream' 
 
 
 
我已经阅读了关于.cpp文件中的静态成员的信息，但是我不知道如何使用fstream的
解决方案
您需要定义其中定义测试方法的流：
  std :: ofstream Test :: outStream; 
 std :: ifstream测试:: inStream; 
  
 
I have this definition for my Test class:
#ifndef TEST_H
#define TEST_H

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <fstream>

class Test {
      public:
          static bool testAll(bool debug = false);           
      private:
          static bool testVector2D(bool debug = false);
          static bool testPolygon(bool debug = false);
          static bool testRectangle(bool debug = false);
          static bool testMap(bool debug = false);

          static std::ofstream outStream;
          static std::ifstream inStream;

          static void prepareWriting();
          static void prepareReading();

          const char tempFileName[];
};   
When I try to use Test::outStream or Test::inStream, for example here:
void Test::prepareWriting() {
    if (Test::inStream.is_open()) {
        Test::inStream.close();
    }
    Test::outStream.open(testFileName,ios::out); 
}
I get this msg: "undefined reference to `Test::inStream'"

I have read something about inicializating the static members in the .cpp file, but I don't know how to do that with fstream's
解决方案
You need to define the streams where you define the other Test methods:
std::ofstream Test::outStream;
std::ifstream Test::inStream;


                        
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