c++ - 错误 LNK2001/LNK2009：未解析的外部符号

Question

我的代码有一点小问题，我认为我错过了某些东西或不明白。

这是我的代码，它基本上从 .txt 文件中读取数据并将数组分配给浮点数。在另一个 .cpp 中，我想将此数组分配给另一个变量，但总是出现错误：

TxtToArrayV2.cpp：

#include<iostream>
#include<fstream>
#include<string>
#include "TxtToArrayV2.h"

using namespace std;

// This program read the data from two files and extract the char data from it being after converted into a float number.

int main()
{
    ifstream foutRPM;
    ifstream foutTorque;

    foutRPM.open("rpmIRLBerlin.txt");
    foutTorque.open("torqueIRLBerlin.txt");

    char valueRPM[1000];
    char valueTorque[1000];

    while (!foutRPM.eof() & !foutTorque.eof())
    {
        foutRPM.getline(valueRPM, 10000);
        foutTorque.getline(valueTorque, 10000);

        // conversion from char to float: more info on https://www.programiz.com/cpp-programming/string-float-conversion 
        float RPM = stof(valueRPM);
        float Torque_Nm = stof(valueTorque);
        cout << RPM << "\n";
        cout << Torque_Nm << "\n";
    }

    foutRPM.close();
    foutTorque.close();

    system("pause");
    return 0;
}

TxtToArrayV2.h

#ifndef __TXT_TO_ARRAY_V2_H__
#define __TXT_TO_ARRAY_V2_H__

extern float RPM;
extern float Torque_Nm;


#endif

源.cpp：

#include "TxtToArrayV2.h"
#include<iostream>
#include<fstream>
#include<string>

void SomeFunctio()
{
    double lala = RPM;
}

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