questiontype.php

很棒的在线教学系统

                fwrite ($bf,full_tag("ANSWER",$level+1,false,$calculated->answer));
                fwrite ($bf,full_tag("TOLERANCE",$level+1,false,$calculated->tolerance));
                fwrite ($bf,full_tag("TOLERANCETYPE",$level+1,false,$calculated->tolerancetype));
                fwrite ($bf,full_tag("CORRECTANSWERLENGTH",$level+1,false,$calculated->correctanswerlength));
                fwrite ($bf,full_tag("CORRECTANSWERFORMAT",$level+1,false,$calculated->correctanswerformat));
                //Now backup numerical_units
                $status = question_backup_numerical_units($bf,$preferences,$question,7);
                //Now backup required dataset definitions and items...
                $status = question_backup_datasets($bf,$preferences,$question,7);
                //End calculated data
                $status = $status &&fwrite ($bf,end_tag("CALCULATED",$level,true));
            }
            //Now print question_answers
            $status = question_backup_answers($bf,$preferences,$question);
        }
        return $status;
    }

/// RESTORE FUNCTIONS /////////////////

    /*
     * Restores the data in the question
     *
     * This is used in question/restorelib.php
     */
    function restore($old_question_id,$new_question_id,$info,$restore) {

        $status = true;

        //Get the calculated-s array
        $calculateds = $info['#']['CALCULATED'];

        //Iterate over calculateds
        for($i = 0; $i < sizeof($calculateds); $i++) {
            $cal_info = $calculateds[$i];
            //traverse_xmlize($cal_info);                                                                 //Debug
            //print_object ($GLOBALS['traverse_array']);                                                  //Debug
            //$GLOBALS['traverse_array']="";                                                              //Debug

            //Now, build the question_calculated record structure
            $calculated->question = $new_question_id;
            $calculated->answer = backup_todb($cal_info['#']['ANSWER']['0']['#']);
            $calculated->tolerance = backup_todb($cal_info['#']['TOLERANCE']['0']['#']);
            $calculated->tolerancetype = backup_todb($cal_info['#']['TOLERANCETYPE']['0']['#']);
            $calculated->correctanswerlength = backup_todb($cal_info['#']['CORRECTANSWERLENGTH']['0']['#']);
            $calculated->correctanswerformat = backup_todb($cal_info['#']['CORRECTANSWERFORMAT']['0']['#']);

            ////We have to recode the answer field
            $answer = backup_getid($restore->backup_unique_code,"question_answers",$calculated->answer);
            if ($answer) {
                $calculated->answer = $answer->new_id;
            }

            //The structure is equal to the db, so insert the question_calculated
            $newid = insert_record ("question_calculated",$calculated);

            //Do some output
            if (($i+1) % 50 == 0) {
                if (!defined('RESTORE_SILENTLY')) {
                    echo ".";
                    if (($i+1) % 1000 == 0) {
                        echo "<br />";
                    }
                }
                backup_flush(300);
            }

            //Now restore numerical_units
            $status = question_restore_numerical_units ($old_question_id,$new_question_id,$cal_info,$restore);

            //Now restore dataset_definitions
            if ($status && $newid) {
                $status = question_restore_dataset_definitions ($old_question_id,$new_question_id,$cal_info,$restore);
            }

            if (!$newid) {
                $status = false;
            }
        }

        return $status;
    }

/**
   * Runs all the code required to set up and save an essay question for testing purposes.
   * Alternate DB table prefix may be used to facilitate data deletion.
   */
  function generate_test($name, $courseid = null) {
      list($form, $question) = parent::generate_test($name, $courseid);
      $form->feedback = 1;
      $form->multiplier = array(1, 1);
      $form->shuffleanswers = 1;
      $form->noanswers = 1;
      $form->qtype ='calculated';
      $question->qtype ='calculated';
      $form->answers = array('{a} + {b}');
      $form->fraction = array(1);
      $form->tolerance = array(0.01);
      $form->tolerancetype = array(1);
      $form->correctanswerlength = array(2);
      $form->correctanswerformat = array(1);
      $form->questiontext = "What is {a} + {b}?";

      if ($courseid) {
          $course = get_record('course', 'id', $courseid);
      }

      $new_question = $this->save_question($question, $form, $course);

      $dataset_form = new stdClass();
      $dataset_form->nextpageparam["forceregeneration"]= 1;
      $dataset_form->calcmin = array(1 => 1.0, 2 => 1.0);
      $dataset_form->calcmax = array(1 => 10.0, 2 => 10.0);
      $dataset_form->calclength = array(1 => 1, 2 => 1);
      $dataset_form->number = array(1 => 5.4 , 2 => 4.9);
      $dataset_form->itemid = array(1 => '' , 2 => '');
      $dataset_form->calcdistribution = array(1 => 'uniform', 2 => 'uniform');
      $dataset_form->definition = array(1 => "1-0-a",
                                        2 => "1-0-b");
      $dataset_form->nextpageparam = array('forceregeneration' => false);
      $dataset_form->addbutton = 1;
      $dataset_form->selectadd = 1;
      $dataset_form->courseid = $courseid;
      $dataset_form->cmid = 0;
      $dataset_form->id = $new_question->id;
      $this->save_dataset_items($new_question, $dataset_form);

      return $new_question;
  }
}
//// END OF CLASS ////

//////////////////////////////////////////////////////////////////////////
//// INITIATION - Without this line the question type is not in use... ///
//////////////////////////////////////////////////////////////////////////
question_register_questiontype(new question_calculated_qtype());

function qtype_calculated_calculate_answer($formula, $individualdata,
        $tolerance, $tolerancetype, $answerlength, $answerformat='1', $unit='') {
/// The return value has these properties:
/// ->answer    the correct answer
/// ->min       the lower bound for an acceptable response
/// ->max       the upper bound for an accetpable response

    /// Exchange formula variables with the correct values...
    global $QTYPES;
    $answer = $QTYPES['calculated']->substitute_variables($formula, $individualdata);
    if ('1' == $answerformat) { /* Answer is to have $answerlength decimals */
        /*** Adjust to the correct number of decimals ***/
        if (stripos($answer,'e')>0 ){
            $answerlengthadd = strlen($answer)-stripos($answer,'e');
        }else {
            $answerlengthadd = 0 ;
        }
        $calculated->answer = round(floatval($answer), $answerlength+$answerlengthadd);

        if ($answerlength) {
            /* Try to include missing zeros at the end */

            if (ereg('^(.*\\.)(.*)$', $calculated->answer, $regs)) {
                $calculated->answer = $regs[1] . substr(
                        $regs[2] . '00000000000000000000000000000000000000000x',
                        0, $answerlength)
                        . $unit;
            } else {
                $calculated->answer .=
                        substr('.00000000000000000000000000000000000000000x',
                        0, $answerlength + 1) . $unit;
            }
        } else {
            /* Attach unit */
            $calculated->answer .= $unit;
        }

    } else if ($answer) { // Significant figures does only apply if the result is non-zero

        // Convert to positive answer...
        if ($answer < 0) {
            $answer = -$answer;
            $sign = '-';
        } else {
            $sign = '';
        }

        // Determine the format 0.[1-9][0-9]* for the answer...
        $p10 = 0;
        while ($answer < 1) {
            --$p10;
            $answer *= 10;
        }
        while ($answer >= 1) {
            ++$p10;
            $answer /= 10;
        }
        // ... and have the answer rounded of to the correct length
        $answer = round($answer, $answerlength);

        // Have the answer written on a suitable format,
        // Either scientific or plain numeric
        if (-2 > $p10 || 4 < $p10) {
            // Use scientific format:
            $eX = 'e'.--$p10;
            $answer *= 10;
            if (1 == $answerlength) {
                $calculated->answer = $sign.$answer.$eX.$unit;
            } else {
                // Attach additional zeros at the end of $answer,
                $answer .= (1==strlen($answer) ? '.' : '')
                        . '00000000000000000000000000000000000000000x';
                $calculated->answer = $sign
                        .substr($answer, 0, $answerlength +1).$eX.$unit;
            }
        } else {
            // Stick to plain numeric format
            $answer *= "1e$p10";
            if (0.1 <= $answer / "1e$answerlength") {
                $calculated->answer = $sign.$answer.$unit;
            } else {
                // Could be an idea to add some zeros here
                $answer .= (ereg('^[0-9]*$', $answer) ? '.' : '')
                        . '00000000000000000000000000000000000000000x';
                $oklen = $answerlength + ($p10 < 1 ? 2-$p10 : 1);
                $calculated->answer = $sign.substr($answer, 0, $oklen).$unit;
            }
        }

    } else {
        $calculated->answer = 0.0;
    }

    /// Return the result
    return $calculated;
}


function qtype_calculated_find_formula_errors($formula) {
/// Validates the formula submitted from the question edit page.
/// Returns false if everything is alright.
/// Otherwise it constructs an error message
    // Strip away dataset names
    while (ereg('\\{[[:alpha:]][^>} <{"\']*\\}', $formula, $regs)) {
        $formula = str_replace($regs[0], '1', $formula);
    }

    // Strip away empty space and lowercase it
    $formula = strtolower(str_replace(' ', '', $formula));

    $safeoperatorchar = '-+/*%>:^~<?=&|!'; /* */
    $operatorornumber = "[$safeoperatorchar.0-9eE]";


    while (ereg("(^|[$safeoperatorchar,(])([a-z0-9_]*)\\(($operatorornumber+(,$operatorornumber+((,$operatorornumber+)+)?)?)?\\)",
            $formula, $regs)) {

        switch ($regs[2]) {
            // Simple parenthesis
            case '':
                if ($regs[4] || strlen($regs[3])==0) {
                    return get_string('illegalformulasyntax', 'quiz', $regs[0]);
                }
                break;

            // Zero argument functions
            case 'pi':
                if ($regs[3]) {
                    return get_string('functiontakesnoargs', 'quiz', $regs[2]);
                }
                break;

            // Single argument functions (the most common case)
            case 'abs': case 'acos': case 'acosh': case 'asin': case 'asinh':
            case 'atan': case 'atanh': case 'bindec': case 'ceil': case 'cos':
            case 'cosh': case 'decbin': case 'decoct': case 'deg2rad':
            case 'exp': case 'expm1': case 'floor': case 'is_finite':
            case 'is_infinite': case 'is_nan': case 'log10': case 'log1p':
            case 'octdec': case 'rad2deg': case 'sin': case 'sinh': case 'sqrt':
            case 'tan': case 'tanh':
                if ($regs[4] || empty($regs[3])) {
                    return get_string('functiontakesonearg','quiz',$regs[2]);
                }
                break;

            // Functions that take one or two arguments
            case 'log': case 'round':
                if ($regs[5] || empty($regs[3])) {
                    return get_string('functiontakesoneortwoargs','quiz',$regs[2]);
                }
                break;

            // Functions that must have two arguments
            case 'atan2': case 'fmod': case 'pow':
                if ($regs[5] || empty($regs[4])) {
                    return get_string('functiontakestwoargs', 'quiz', $regs[2]);
                }
                break;

            // Functions that take two or more arguments
            case 'min': case 'max':
                if (empty($regs[4])) {
                    return get_string('functiontakesatleasttwo','quiz',$regs[2]);
                }
                break;

            default:
                return get_string('unsupportedformulafunction','quiz',$regs[2]);
        }

        // Exchange the function call with '1' and then chack for
        // another function call...
        if ($regs[1]) {
            // The function call is proceeded by an operator
            $formula = str_replace($regs[0], $regs[1] . '1', $formula);
        } else {
            // The function call starts the formula
            $formula = ereg_replace("^$regs[2]\\([^)]*\\)", '1', $formula);
        }
    }

    if (ereg("[^$safeoperatorchar.0-9eE]+", $formula, $regs)) {
        return get_string('illegalformulasyntax', 'quiz', $regs[0]);
    } else {
        // Formula just might be valid
        return false;
    }

}

function dump($obj) {
    echo "<pre>\n";
    var_dump($obj);
    echo "</pre><br />\n";
}

?>