如何在Visual Studio中包含头文件？

Question

I have a problem in VS2012, where I want to include a header file:

#include <FileReader>

The problem is that I want to read a file and store it into a matrix. However, the include directive fails so that I am unable to read it:

#include <mpi.h>
#include <iostream>
#include <FileReader>

int main(int argc, char* argv[]) 
{
int rows, cols;
float a[10];

//std::vector<float> vec;

FileReader fr("./SampleData.txt");

fr.getSize(rows, cols);

fr.getVector(a);

for (int i = 0; i < cols; i++)
    fr.getNextRow(a);

int i;

std::cin >> i;

return 0;
};

Could you please explain why this program does not compile?

Answer 1

The answer depends on what FileReader refers to.

Assuming that it refers to a header file for a class you designed yourself:

1. Your should rename this header file into FileReader.h , as names without extension are by convention reserved to the compiler libraries;
2. You should then enclose the header file name between double-quotes rather than angular brackets, as angular brackets are to be used for compiler libraries, or possibly for third-party libraries used in your project ( boost ...)

Thus, once FileReader is renamed into FileReader.h , the include directive should looks as shown below:

`#include "FileReader.h"`

UPDATE

The additional errors you encounter are *linker errors'. They mean that:

• Compilation of your source files works fine;
• However, some methods are declared in FileReader.h but no compiled code can be found for these methods.

The most likely explanation is that the source code for these methods is not included in the project. Thus, you must add this source code to your VS project. It is probably a file named FileReader.c or FileReader.cpp .