求表达式的值

1.测试代码

public class MyClass
    {
        public static void Run()
        {
            KExpression exp = new KExpression();
            string backExp = exp.GetRPN("1+3*(4+6/2)");
            string value = exp.GetValue(backExp);
        }
    }

2.把计算公式转后缀表达式，去掉其中的括号

/// <summary>
        /// 把中缀表达式转为后缀表达式
        /// </summary>
        /// <param name="p"></param>
        /// <returns></returns>
        public string GetRPN(string p)
        {
            Stack<char> stack = new Stack<char>();
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < p.Length; i++)
            {
                char h = p[i];
                if (IsOperator(h) && stack.Count == 0)//rule 2如果是操作数并且栈为空，把操作数入栈
                {
                    stack.Push(h);
                }
                else if (char.IsDigit(h))// rule 1
                {
                    sb.Append(h);
                }
                else if (h == '(') //rule 3
                {
                    stack.Push(h);
                }
                else if (h == ')') //rule 4 找出与该括号匹配的左括号
                {
                    while (true)
                    {
                        var t = stack.Pop();
                        if (t == '(')
                        {
                            break;
                        }
                        sb.Append(t);
                    }
                }
                else if (IsOperator(h) && stack.Count > 0)//rule 5
                {
                    var t = stack.Peek();
                    if (Prop(t) >= Prop(h))
                    {
                        t = stack.Pop();
                        sb.Append(t);
                    }
                    else
                    {
                        stack.Push(h);
                    }
                }

            }
            while (stack.Count > 0)
            {
                var t = stack.Pop();
                sb.Append(t);
            }
            return sb.ToString();
        }