Title: An Exercise - Source unknown

#include <stdio.h>

int main(int argc, char **argv) {
  int ch;
  FILE *infile = fopen(argv[1], "rb");

  while (EOF != (ch=getc(infile))) 
    if ( ch == '\r' )
      putchar('\n');
    else
      putchar(ch);
  fclose(infile);
  return 0;
}

Beginner's exercise: test program.

Intermediate exercise: add error-checking.

Advanced exercise: add really good error-checking.

Idiot Pedant exercise: identify all portions of this program that are not strictly conforming and identify ways of rewriting the standard to allow a program with similar functionality to be strictly conforming.

For Everyone: What does it do? (hint: think about-of-line encoding on different platforms