[HaBo]

while(!in.eof())
{
in.get(temp,20);
cout << temp;
out << temp;
}

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

int main(int argc, char *argv[])
{
    char c;
    FILE *in_file;
    FILE *out_file;
    
    in_file = fopen("Servus.txt", "r");
    
    if(!in_file)
    {
        fprintf(stderr, "Datei konnte nicht geoffnet werden");
        return -1;
    }
    
    out_file = fopen("Kopie.txt", "w");
    
    if(!out_file)
    {
        fprintf(stderr, "Datei konnte nicht geoffnet werden");
        return -1;
    }
    
    while(( c = (char)fgetc(in_file)) != EOF)
    {
        fprintf(stdout, "%c", c);
        fprintf(out_file, "%c", c);
    }
    
    getch();
}

#include <cstdlib>
#include <iostream>
#include <fstream>

using namespace std;

int main(int argc, char *argv[])
{
    fstream in;
    in.open("Servus.txt", ios::in);
    
    if(!in)
    {
        cerr << "Datei konnte nicht geoeffnet werden";
        return -1;
    }
    
    fstream out;
    out.open("Kopie.txt", ios::out);
    
    if(!out)
    {
        cerr << "Datei konnte nicht geoffnet werden";
        return -1;
    }
    
    char c;
    while(in.get(c))
    {
        cout << c;
        out.put(c);
    }
        
    in.close();
    out.close();
    
    getchar();
}

while(in.get(temp))