fileio2.cpp

Code

/*
    fileio2.cpp
    David Klick
    CIS 250
    2017-10-06

    demonstration of binary file I/O
*/
#include <fstream>
#include <iostream>
using std::cout;
using std::endl;
using std::ifstream;
using std::ofstream;
using std::ios;

int main(void) {
    int n;
    float x = 0.0f;

    // specify binary when opening file
    ofstream ofile("testfileio2.txt", ios::binary);
    if (!ofile) {
        cout << "Error: couldn't open output file" << endl;
        return 1;
    }

    // use write function to write binary data
    for (n=1; n<10; n++, x+=25) {
        ofile.write(reinterpret_cast<char *>(&n), sizeof(n));
        ofile.write(reinterpret_cast<char *>(&x), sizeof(x));
    }
    ofile.close();

    // specify binary when opening file
    ifstream ifile("testfileio2.txt", ios::binary);
    if (!ifile) {
        cout << "Error: couldn't open input file" << endl;
        return 2;
    }

    // use priming read and loop to read all records
    ifile.read(reinterpret_cast<char *>(&n), sizeof(n));
    ifile.read(reinterpret_cast<char *>(&x), sizeof(x));
    while (ifile) {
        cout << n << ", " << x << endl;
        ifile.read(reinterpret_cast<char *>(&n), sizeof(n));
        ifile.read(reinterpret_cast<char *>(&x), sizeof(x));
    }
    ifile.close();

    return 0;
}