// copy stdin to stdout line-by-line using fgets() and fputs()
//
#include <stdio.h>
#include <ctype.h>

int main( void)
{
  char line[BUFSIZ]; // line[0] is a char, &line[0] == line

  printf( "BUFSIZ = %i\n", BUFSIZ);

  while(1) {

    if( fgets( line, BUFSIZ, stdin) == NULL) break;

    fputs( line, stdout);

   // upper case
    for( char *p = line; *p; ++p) *p = toupper(*p);
    fputs( line, stdout);
  }
}