Online PHP editor | refs for kUkpK

<?php $grades=array(-4,-1,0,1,6,10,70,99,100,101,105,110); foreach($grades as $grade){ if( ($grade+1)*(101-$grade) > 0 ){ // ($grade minus negative [lower limit])*([upper limit] plus $grad) $validGrades[] = $grade; }else{ $invalidGrades[] = $grade; } } var_export($validGrades); var_export($invalidGrades);