// copy pairs of doubles from standard input to standard output
 
#include <stdio.h>
 
int main( void)
{
  int s; // scanf return status
 
  double d1, d2;
 
  while( 1) // until end-of-file or error
  {
    s = scanf("%lf%lf",&d1,&d2); // try to read two doubles
 
    if( s != 2) // could not read two doubles, must be end-of-file or error
      break;
 
    printf( "%g %g\n", d1, d2);
  }
 
  return 0;
}

/* sample run:

$ echo "1.1 2.2 3.3 4.4 5.5 abc 6.6" | ./a.out
1.1 2.2
3.3 4.4
$