CPP

c++ open file

// Reading a file

#include <iostream>
#include <fstream>
#include <string>

int main() 
{
    std::string line;

    std::ifstream file("example.txt");
    if(file.is_open())
    {
        while(getline(file, line))
        {
            std::cout << line << '
';
        }
        file.close();
    }
    else std::cout << "Unable to open file";

    return 0;
}

file open cpp

#include <iostream>
#include <fstream>
using namespace std;

int main () {
  ofstream myfile;
  myfile.open ("file.txt");
  myfile << "Writing to a file.
";
  myfile.close();
  return 0;
}

c++ read file

#include <stdio.h>

#define n 1024 // n bytes

int main(void) {
	FILE *fp;
    size_t numread;
    if ((fp = fopen("yourfile.xy", "rb") != NULL) {
    	char buffer[n];
        numread = fread(buffer, sizeof(*buffer), n, fp);
      	printf("Read %d Bytes: %s", numread, buffer);
      
      	fclose(fp);
      	return 0;
    }
        
    return -1;
}

files c++

fstream  afile;
afile.open("file.dat", ios::out | ios::in );