Exiting a while loop at EOF using scanf in C

Question

I\'m writing a few very small programs for my introductory C course. One of them requires me to read in double values, one number per line, and then print out basic statisti

Answer 1

The below code is a simplification of your I/O issues.

" %lf " supplies 3 scanf() format directives: 1) white-space 2) double specifier, 3) white-space.

The first white-space directive is not needed as the %lf allows for optional leading whitespace. The 2nd white-space directive causes problems as it consumes the Enter key, waiting for additional input.

"%lf" supplies 1 scanf() format directives: double specifier

This consumes optional leading white-space, including any previous \n, then scans for and hopefully decodes a double. A \n (Enter key) following the number is left in the input buffer for the next input (the next scanf()).

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Now as to why your control Z is failing. It appears your console is consuming the ^Z and performing a "suspend job". My console, instead of giving the ^Z to the program, closes the stdin input. In essence putting an EOF in stdin.

So you need to either:
1) Find your console's mechanism for closing the stdin - others have suggested ^D.
2) Use an alternative to exit your loop. I suggest result != 1 which readily occurs when non-numeric input is entered.

#include <stdio.h>
int main(int argc, char *argv[]) {
  int result;
  double x = 0.0;
  do {
    // result = scanf(" %lf ", &x);  /* Your original format */
    result = scanf("%lf", &x);
    printf("%d %lf\n", result, x);
    fflush(stdout);  // Your system may not need this flush
  } while (result != EOF);
}

Answer 2

Okay guys, after giving up on this first part of the project and debugging the other parts, I have determined that my only issue with the code above is I am trying to reference an index of an array that is out of bounds. I have also determined that the EOF key is ctrl-d, even though I have read and been told by my professor that it is ctrl-z for windows. Regardless, this should be an easy fix. Thanks so much to everyone who provided input!