/// <summary>
/// 解析通用表达式
/// </summary>
/// <param name="expression">表达式字符串</param>
/// <returns>表达式结点树</returns>
private ExpressionNode ExpressionParse(string expression)
{
int leftBracketsIndex = 0;
int rightBracketsIndex = -1;
string subExpression = string.Empty;
string subExpressionValue = string.Empty;
while (true)
{
for (int i = 0; i < expression.Length; i++)
{
if (expression[i] == Operators.LeftBrackets)
{
leftBracketsIndex = i;
continue;
}
if (expression[i] == Operators.RightBrackets)
{
rightBracketsIndex = i;
subExpression = expression.Substring(leftBracketsIndex + 1, rightBracketsIndex - leftBracketsIndex - 1);
subExpressionValue = this.Calculator(this.BlendExpressionParse(subExpression)).ToString();
expression = expression.Remove(leftBracketsIndex + 1, rightBracketsIndex - leftBracketsIndex - 1);
expression = expression.Insert(leftBracketsIndex + 1, subExpressionValue);
if (expression[leftBracketsIndex] == Operators.LeftBrackets &&
expression[leftBracketsIndex + subExpressionValue.Length + 1] == Operators.RightBrackets)
{
if (subExpressionValue[0] == Operators.Subtraction)
{
if (leftBracketsIndex == 0)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 1);
}
else if (leftBracketsIndex > 0)
{
switch (expression[leftBracketsIndex - 1])
{
case Operators.Add:
//3-(2+(-2)*4+5)+25
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
expression = expression.Remove(leftBracketsIndex - 1, 1);
expression = expression.Insert(leftBracketsIndex - 1, "-");
//3-(2-2*4+5)+25
break;
case Operators.Subtraction:
//3-(2-(-2)*4+5)+25
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
expression = expression.Remove(leftBracketsIndex - 1, 1);
expression = expression.Insert(leftBracketsIndex - 1, "+");
//3-(2+2*4+5)+25
break;
case Operators.Multiply:
case Operators.Division:
//1. 3-2*(-2)*4+25
//2. 3+2*(-2)*4+25
//3. 6.5/(-2)*0.5
bool isProcessed = false;
for (int j = leftBracketsIndex - 1 - 1; j >= 0; j--)
{
if (expression[j] == Operators.LeftBrackets)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
expression = expression.Insert(j + 1, "-");
isProcessed = true;
break;
}
if (expression[j] == Operators.Add)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
expression = expression.Remove(j, 1);
expression = expression.Insert(j, "-");
isProcessed = true;
break;
//3-2*2*4+25
}
else if (expression[j] == Operators.Subtraction)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
expression = expression.Remove(j, 1);
expression = expression.Insert(j, "+");
isProcessed = true;
break;
//3+2*2*4+25
}
}
if (!isProcessed)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 2);
if (expression[0] == Operators.Subtraction)
{
expression = expression.Remove(0, 1);
}
else
{
expression = expression.Insert(0, "-");
}
}
//1. 3+2*2*4+25
//2. 3-2*2*4+25
//3. -6.5/2*0.5
break;
case Operators.LeftBrackets:
//3-((-2)*4+5)+25
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 1);
//3-(-2*4+5)+25
break;
default:
throw new Exception("未知的运算符:" + expression[leftBracketsIndex - 1 - 1].ToString());
}
}
else
{
throw new Exception("未知索引");
}
}
else
{
if (leftBracketsIndex == 0)
{
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 1);
}
else if (leftBracketsIndex > 0)
{
switch (expression[leftBracketsIndex - 1])
{
case Operators.Add:
case Operators.Subtraction:
case Operators.Multiply:
case Operators.Division:
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex, 1);
break;
case Operators.LeftBrackets:
expression = expression.Remove(leftBracketsIndex + subExpressionValue.Length + 1, 1);
expression = expression.Remove(leftBracketsIndex - 1, 1);
break;
default:
throw new Exception("未知的运算符:" + expression[leftBracketsIndex - 1 - 1].ToString());
}
}
else
{
throw new Exception("未知索引");
}
}
}
break;
}
}
if (!expression.Contains(Operators.LeftBrackets) && !expression.Contains(Operators.RightBrackets))
{
break;
}
}
ExpressionNode root = this.BlendExpressionParse(expression);
return(root);
}
/// <summary>
/// 仅加法和减法或仅乘法和除法(不能有加减和乘除混合)表达式解析生成树
/// </summary>
/// <param name="expression">要计算的表达式字符串</param>
/// <returns>表达式节点树</returns>
private ExpressionNode BaseExpressionParse(string expression)
{
ExpressionNode root = new ExpressionNode();
int valueStaratIndex = 0;
string value = string.Empty;
char chDefaultValue = default(char);
char currentOperator = chDefaultValue;
for (int i = 0; i < expression.Length; i++)
{
if (BaseCalate.IsOperator(expression[i]))
{
value = expression.Substring(valueStaratIndex, i - valueStaratIndex);
valueStaratIndex = i + 1;
currentOperator = expression[i];
continue;
}
else
{
if (!string.IsNullOrEmpty(value) && currentOperator != chDefaultValue)
{
if (root.Left == null)
{
var lefttLeafNode = new ExpressionNode();
lefttLeafNode.Value = double.Parse(value.Trim());
lefttLeafNode.Parent = root;
root.Operator = currentOperator;
root.Left = lefttLeafNode;
}
else if (root.Left != null && root.Right == null)
{
var rightLeafNode = new ExpressionNode();
rightLeafNode.Value = double.Parse(value.Trim());
rightLeafNode.Parent = root;
root.Right = rightLeafNode;
var parentNode = new ExpressionNode();
parentNode.Operator = currentOperator;
parentNode.Left = root;
root.Parent = parentNode;
root = parentNode;
}
value = string.Empty;
}
}
}
value = expression.Substring(valueStaratIndex, expression.Length - valueStaratIndex);
if (root.Left != null)
{
var endLeaf = new ExpressionNode();
endLeaf.Value = double.Parse(value.Trim());
endLeaf.Parent = root;
root.Right = endLeaf;
}
else
{
root.Value = double.Parse(value.Trim());
}
return(root);
}
/// <summary>
/// 无括号的加减乘除混合表达式运算
/// </summary>
/// <param name="expression">要计算的表达式字符串</param>
/// <returns>表达式节点树</returns>
private ExpressionNode BlendExpressionParse(string expression)
{
int startSubExpressionIndex = 0;
int endSubExpressionIndex = -1;
string subExpression = string.Empty;
double subExpressionValue = 0.0d;
if (expression[0] == Operators.Subtraction)
{
expression = "0" + expression;
}
while (true)
{
for (int i = 0; i < expression.Length; i++)
{
if (expression[i] == Operators.Multiply || expression[i] == Operators.Division)
{
if (i + 1 == expression.Length)
{
endSubExpressionIndex = i + 1;
}
else
{
for (int j = i + 1; j < expression.Length; j++)
{
if (BaseCalate.IsOperator(expression[j]))
{
endSubExpressionIndex = j;
break;;
}
}
if (endSubExpressionIndex == -1)
{
endSubExpressionIndex = expression.Length;
}
}
subExpression = expression.Substring(startSubExpressionIndex, endSubExpressionIndex - startSubExpressionIndex);
subExpressionValue = BaseCalate.BaseCal(subExpression);
expression = expression.Remove(startSubExpressionIndex, endSubExpressionIndex - startSubExpressionIndex);
expression = expression.Insert(startSubExpressionIndex, subExpressionValue.ToString());
endSubExpressionIndex = -1;
break;
}
if (expression[i] == Operators.Add || expression[i] == Operators.Subtraction)
{
startSubExpressionIndex = i + 1;
}
}
if (!expression.Contains(Operators.Multiply) && !expression.Contains(Operators.Division))
{
break;
}
}
ExpressionNode root = BaseExpressionParse(expression);
return(root);
}
