/// <summary>
/// 将字符串解析为中序表达式
/// </summary>
/// <param name="str">要解析的字符串</param>
/// <returns>一个中序表达式结构体</returns>
static public MiddleExpression TurnToMiddle(string str)
{
string s = str.Replace(" ", "");
MiddleExpression m = new MiddleExpression();
CalcNode LastNode = new CalcNode(NodeType.Num);
char[] cs = s.ToCharArray();
LastNode = null;
foreach (char c in cs)
{
if (c >= 48 && c <= 57)
{
if (LastNode != null && LastNode.Type == NodeType.Num)
{
LastNode.Num = LastNode.Num * 10 + c - 48;
}
else
{
LastNode = CalcNode.FromDouble(c - 48.0);
m.Add(LastNode);
}
}
else if (Operators.Contains(c))
{
LastNode = CalcNode.FromChar(c);
m.Add(LastNode);
}
else
{
if (LastNode != null && LastNode.Type == NodeType.Variable)
{
LastNode.Value += c;
}
else
{
LastNode = new CalcNode(NodeType.Variable);
LastNode.Value = c.ToString();
m.Add(LastNode);
}
}
}
// 检查是否有计算节点是函数
foreach (CalcNode node in m)
{
if (node.Type == NodeType.Variable)
{
if (Functions.Contains(node.Value))
{
node.Type = NodeType.Function;
}
}
}
return(m);
}
static public MiddleExpression TurnToMiddle(string str)
{
string s = str.Replace(" ", "");
MiddleExpression m = new MiddleExpression();
CalcNode LastNode = new CalcNode(NodeType.Num);
char[] cs = s.ToCharArray();
LastNode = null;
foreach (char c in cs)
{
if (c >= 48 && c <= 57)
{
if (LastNode != null && LastNode.Type == NodeType.Num)
{
LastNode.Num = LastNode.Num * 10 + c - 48;
}
else
{
LastNode = CalcNode.FromDouble(c - 48.0);
m.Add(LastNode);
}
}
else if (c == '+' || c == '-' || c == '*' || c == '/' || c == '%' || c == '^' || c == '(' || c == ')')
{
LastNode = CalcNode.FromChar(c);
m.Add(LastNode);
}
else
{
LastNode = new CalcNode(NodeType.Variable);
LastNode.Value = c;
m.Add(LastNode);
}
}
return(m);
}