read first line from a file and write to a new file

[thenewbiecoder]

I'm just starting to learn c++ and need to know how would you read the first line from a file and write to a new file? thanks

[Cross213]

Did you perhaps try and could you show us your progress so far?

[thenewbiecoder]

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

int main()
{
    ifstream in;
    in.open("file.dat");
    
    if(!in) 
    {
        cout << "Cannot open input file.\n";
        return 1;
    }
    
    
    char num[15];
    
    while(in) 
    {
        in.getline(num, 15);
        cout << num << endl;
    }
    
    in.close();
    return 0;
}

This is print out all the data in the file but I want it to read each line for the file and have it print to a new file..

[NathanOliver]

well you need an ofstream object opened to the file that you want. after you do that in for loop output the char array to the file using the >> operator.

[thenewbiecoder]

int main ()
{
    int getFirstLine;
    ifstream inFile;
    ofstream outFile;
    

    inFile.open("originalFile.dat");
    outFile.open("File1.dat");
    
    inFile >> getFirstLine;
    
    outFile << fixed << "Get First One:  " << setprecision(2) << getFirstLine <<endl;
    
    inFile.close();
    outFile.close();
}

basically, this revised code only write the first line to new file (File1.dat) from the original file. How do I get it to write 15 lines(because originalFile.dat contains 15 lines) to 15 different separate .dat files? I think I need to do an array or some sort but I can't figure it out. If anyone can help me.... thanks

[WaltP]

You have to create the "file1.dat" filename each time through your loop. You need stringstream or sprintf or something similar to do that.