error LNK2019: unresolved external symbol - c++

Question

Ok, so I'm having a problem trying figure out the problem in my code. I have a lot of code so I'm only going to post the relevant parts that are messing up when I compile. I have the following function inside of a class and it will compile and everything will run fine until I call the function "CalculateProbabilityResults" and it runs the 7th line of code within it. I've "de-commented" this line of code in my program so you can find it easier. I'm pretty sure I have the right #include directives needed since it compiles fine when not calling the function, so that can't be the problem can it? I know some of my naming notation needs a little help, so please bear with me. Thanks in advance for the help guys.
int SQLServer::CalculateProbabilityResults(int profile, int frame, int time_period, int TimeWindowSize) {
ofstream ResultFile;
stringstream searchFileName;
stringstream outputName;
vector<vector<int>> timeFrameItemsets;
int num = getTimeFrameFile(frame*TimeWindowSize, TimeWindowSize);
cout << num << endl;
//outputName << "Results" << getTimeFrameFile((frame*TimeWindowSize), TimeWindowSize) << ".csv";
cout << outputName.str() << endl;
outputName.clear();
//ResultFile.open(outputName.str().c_str());
ResultFile.close();
result.resize(0);
return 0;
}
int getTimeFrameFile(int timeInHours, int timeFrameSize) {
int fileNum = 0;
int testWin;
if (timeInHours > 24) {
while (timeInHours >24)
timeInHours -= 24;
}
for (testWin = 0; testWin < 24/timeFrameSize; testWin++) {
if (timeInHours >= testWin*timeFrameSize && timeInHours < (testWin+1)*timeFrameSize)
fileNum = testWin+1;
}
if (fileNum == 0)
fileNum = testWin+1;
return fileNum;
}
Call Log
1>------ Rebuild All started: Project: MobileSPADE_1.3, Configuration: Debug Win32 ------
1>Deleting intermediate and output files for project 'MobileSPADE_1.3', configuration 'Debug|Win32'
1>Compiling...
1>main.cpp
1>MobileSPADE.cpp
1>SQLServer.cpp
1>Generating Code...
1>Compiling manifest to resources...
1>Microsoft (R) Windows (R) Resource Compiler Version 6.0.5724.0
1>Copyright (C) Microsoft Corporation. All rights reserved.
1>Linking...
1>LINK : C:\Users\JoshBradley\Desktop\MobileSPADE_1.3\MobileSPADE_1.3\Debug\MobileSPADE_1.3.exe not found or not built by the last incremental link; performing full link
1>SQLServer.obj : error LNK2019: unresolved external symbol "public: int __thiscall SQLServer::getTimeFrameFile(int,int)" (?getTimeFrameFile#SQLServer##QAEHHH#Z) referenced in function "public: int __thiscall SQLServer::CalculateProbabilityResults(int,int,int,int)" (?CalculateProbabilityResults#SQLServer##QAEHHHHH#Z)
1>C:\Users\JoshBradley\Desktop\MobileSPADE_1.3\MobileSPADE_1.3\Debug\MobileSPADE_1.3.exe : fatal error LNK1120: 1 unresolved externals
1>Build log was saved at "file://c:\Users\JoshBradley\Desktop\MobileSPADE_1.3\MobileSPADE_1.3\MobileSPADE_1.3\Debug\BuildLog.htm"
1>MobileSPADE_1.3 - 2 error(s), 0 warning(s)
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

Answer 1

The compiler thinks that getTimeFrameFile is a SQLServer method:
unresolved external symbol "public: int __thiscall SQLServer::getTimeFrameFile(int,int)"
but you have it defined as a free function:
int getTimeFrameFile(int timeInHours, int timeFrameSize) {
Change that from a free function to a class method will solve the problem:
int SQLServer::getTimeFrameFile(int timeInHours, int timeFrameSize)

Answer 2

Put the function getTimeFrameFile above SQLServer::CalculateProbabilityResults.