/// <summary>
/// 計算式作成
/// </summary>
/// <param name="parameter">計算式參數類</param>
/// <returns>計算式對象</returns>
/// <exception cref="ArgumentNullException"><paramref name="parameter"/>為NULL的情況</exception>
public virtual Formula CreateFormula(ArithmeticParameter parameter)
{
Guard.ArgumentNotNull(parameter, "parameter");
Formula = new Formula();
// 随机下限值
MinimumLimit = parameter.MinimumLimit;
// 默認填空項是答案項
Formula.Gap = GapFilling.Answer;
if (parameter.QuestionType == QuestionType.GapFilling)
{
// 對在等式中的三個數值隨機產生填空項（用於填空題型）
Formula.Gap = CommonUtil.GetRandomNumber(GapFilling.Left, GapFilling.Answer);
}
return(Formula);
}
/// <summary>
/// 由計算結果推算出計算式(使用場景:水果連連看)
/// </summary>
/// <param name="parameter">計算式參數類</param>
/// <param name="answer">計算結果</param>
/// <returns>計算式對象</returns>
/// <exception cref="ArgumentNullException"><paramref name="parameter"/>為NULL的情況</exception>
public virtual Formula CreateFormulaWithAnswer(ArithmeticParameter parameter, int answer)
{
Guard.ArgumentNotNull(parameter, "parameter");
return(CreateFormula(parameter));
}
/// <summary>
/// 構造用於計算接龍題型(即：計算式左邊值等於上一個計算式的結果值)
/// </summary>
/// <param name="parameter">計算式參數類</param>
/// <param name="previousFormula">前次推算的計算式對象</param>
/// <returns>計算式對象</returns>
/// <exception cref="ArgumentNullException"><paramref name="parameter"/>為NULL的情況</exception>
public virtual Formula CreateFormula(ArithmeticParameter parameter, Formula previousFormula)
{
Guard.ArgumentNotNull(parameter, "parameter");
return(CreateFormula(parameter));
}
