Reading an int from a file in C++

Question

I'm attempting to open a file and read a series of ints from it in C++. I was under the impression that this could be done by simply using inputfile >> variable. However, even the first item is reading in incorrectly. I wrote the simplest possible code to replicate my problem.

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

int main(int argc, char **argv) {
    int n;

    ifstream inputfile("input.txt");
    inputfile >> n;

    cout << "NUMBER IS: " << n << endl;

    return 0;
}

The input file is simply a text file containing the number 4. However, I get a different large number out every time I test the code. What's the issue?

Answer 1

Add checks like this:

if(inputfile>> n)
{
     //Code
} else
{
    cout << "Failed!";
}

Also, check the file was opened:

ifstream inputfile("input.txt");
if (!inputfile)
{
    cout << "Failed opening file!";
    return -1;
}