VC++ 2010项目中的链接器错误1120。

Question

我正在做我的第一个VC++项目，并使用下面的代码。该项目有以下文件。

Project1.cpp

#include "stdafx.h" 
#include <iostream> 
#include "PopulateDB.h" 

using namespace std; 

int main (void) 
{ 

    PopulateDB x; 
    x.calcUpload(); 


    return 0; 
} 

PopulateDB.h

#pragma once 
#include "mysql_connection.h" 
#include <cppconn/driver.h> 

class PopulateDB 
{ 
public: 
    int calcUpload(void); 
    PopulateDB(void); 
    ~PopulateDB(void); 

private: 

    int updateMA(sql::Connection &); 
}; 

PopulateDB.cpp

#include "StdAfx.h" 
#include "PopulateDB.h" 
#include <iostream> 
#include "mysql_connection.h" 
#include <cppconn/driver.h> 
#include <cppconn/exception.h> 
#include <cppconn/resultset.h> 
#include <cppconn/statement.h> 
#include "Technical.h" 

using namespace std; 

int updateMA(sql::Connection& con) 
{ 
    sql::Statement *stmt; 
    sql::ResultSet *res; 
    int i; 

    stmt = con.createStatement(); 
    res = stmt->executeQuery("SELECT * from PriceAMS"); 

    while(res->next()) 
    { 
     cout << "Symbol " << i << " = " << res->getBlob("Symbol") << endl; 
     i++; 
    } 

    delete stmt; 
} 

int calcUpload(void) 
{ 
    cout << "Running Connection..." << endl; 

    try 
    { 
     sql::Driver *driver; 
     sql::Connection *con; 
     sql::Statement *stmt; 
     sql::ResultSet *res; 

/* Create a connection */ 
     driver = get_driver_instance(); 
     con = driver->connect("tcp://127.0.0.1:3306", "nishantd", "mySQLDB%passWord2013"); //we can initialize the user/pass in constructor 
/* Connect to the MySQL test database */ 
     con->setSchema("testMMDB"); 
     cout << "Looks like it connected..." << endl; 

     updateMA(*con); 

     delete con; 
    } 

    catch (sql::SQLException &e) 
    { 
     cout << "# ERR: SQLException in " << __FILE__; 
     cout << "(" << __FUNCTION__ << ") on line " << __LINE__ << endl; 
     cout << "# ERR: " << e.what(); 
     cout << " (MySQL error code: " << e.getErrorCode(); 
     cout << ", SQLState: " << e.getSQLState() << ")" << endl; 
    } 
    return 0; 
} 


PopulateDB::PopulateDB(void) 
{ 
} 


PopulateDB::~PopulateDB(void) 
{ 
} 

Technical.h

#pragma once 
#include <vector> 

class Technical 
{ 
public: 

    float StandardMovingAverage(std::vector<float> values); 
    float StdDev(std::vector<float> values); 
    float Variance(std::vector<float> values); 
    int RSI(std::vector<float> values); 

    Technical(void); 
    ~Technical(void); 

}; 

Technical.cpp

#include "StdAfx.h" 
#include "Technical.h" 
#include <cmath> 
#include <vector> 

using namespace std; 

float Technical::StandardMovingAverage(vector <float> values) 
{ 
    int sum=0; 
    for(int i=0; i < values.size(); i++) 
     sum+=values[i]; 
    return sum/values.size(); 
} 

float Technical::StdDev(vector <float> values) 
{ 
    float E=0; 
    float ave = StandardMovingAverage(values); //this function just calculates the mean values 
    for(int i=0; i < values.size(); i++) 
     E+=(values[i]- ave)*(values[i]- ave); 
    return sqrt(1/values.size()*E); 
} 

float Technical::Variance(vector <float> values) 
{ 
    return StdDev(values)*StdDev(values); 
} 


Technical::Technical(void) 
{ 
} 


Technical::~Technical(void) 
{ 
} 

我收到以下错误在VC++ 2010年有我目前忽略

1>Project1.obj : error LNK2001: unresolved external symbol "public: int __thiscall PopulateDB::calcUpload(void)" (?calcUpload@PopulateDB@@QAEHXZ) 
1>D:\Project\CPP\Project1\Release\Project1.exe : fatal error LNK1120: 1 unresolved externals 
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== 

我试图解决这一点，让我的代码工作的警告。它更令人沮丧，因为我怀疑我缺少一些非常基本的东西，因为我是VC++的新手，而代码无论如何都没有在当前的形状中做太多工作。

真的很感谢所有帮助

感谢， 尼克

Answer 1

要调用一个名为PopulateDB::calcUpload功能 - PopulateDB类的成员函数。但是你从未真正实现过这个功能。您确实实现了一个名为::calcUpload的不同的，独立的非成员函数，但您并未调用它。

在实现文件中，使其

int PopulateDB::calcUpload() {...}