c++ combine path of file as a string with file name - c++

Question

I want to read some input files in my c++ code and I want to define the path of input files as a string and then combine it with file names. How can I do this? (Input_path + filename.dat)

Answer 1

#include <filesystem> //C++ 17
#include <iostream>
namespace fs = std::filesystem;
using namespace std;
void main()
{
string dir("c:\\temp");
string fileName("my_file.txt");
fs::path fullPath = dir;
fullPath /= fileName;
cout << fullPath.c_str() << endl;
}

Answer 2

You would use something like:
string path ("yourFilePath");
string filename ("filename");
You could then open the file like this:
ifstream inputFileStream;
inputFileStream.open(path + fileName);
Depending on your requirements, you will have to decide whether to use formatted or unformatted input when reading. I would read this for more information regarding that.
Cocatenation referenced from: C++ string concatenation
Reading referenced from: C++ read and write with files

Answer 3

Try any of these codes:
#include <iostream>
#include <string>
#include <fstream>
int main() {
std::string filepath = "D:/location/";
filepath+= "filename.dat";
std::ifstream fp;
fp.open(filepath.c_str(),std::ios_base::binary);
....PROCESS THE FILE HERE
fp.close();
return 0;
}
or
#include <iostream>
#include <string>
#include <fstream>
int main() {
std::string filepath = "D:/location/";
std::ifstream fp;
fp.open((filepath+"filename.dat").c_str(),std::ios_base::binary);
...............
fp.close();
return 0;
}
or use std::string::append
#include <iostream>
#include <string>
#include <fstream>
int main() {
std::string filepath = "D:/location/";
std::ifstream fp;
fp.open((filepath.append("filename.dat")).c_str(),std::ios_base::binary);
fp.close();
return 0;
}