计算器

using System;
using System.Linq;

namespace Calculator
{
    class Program
    {
        static void Main(string[] args)
        {
            for (int i = 0; i < 3; i++)
            {
                string inputStr = Console.ReadLine(); CalcOnline(inputStr);
            }


        }
        static CalcInfo[] configs = new CalcInfo[]
        {
            new CalcInfo("+",(a,b)=>a+b),
            new CalcInfo("-",(a,b)=>a-b),
            new CalcInfo("*",(a,b)=>a*b),
            new CalcInfo("/",(a,b)=>a/b),
        };
        private static void CalcOnline(string inputStr)
        {
            int index = -1;
            Func<float, float, float> func = null;
            for (int i = 0; i < configs.Length; i++)
            {
                var item = configs[i];
                index = inputStr.IndexOf(item.tag);//找到符号，返回所在下标，未找到返回-1
                if (index != -1)
                {
                    func = item.func;//如果找到的是+，那么index为1，+的func函数内容是a+b
                    break;
                }

            }
            if (index == -1)
            {
                Console.WriteLine("只支持+-*/");
                return;
            }
            CalcResult(inputStr, func, index);
        }

        private static void CalcResult(string inputStr, Func<float, float, float> func, int index)
        {
            string num1Str = inputStr.Substring(0, index);//0~index之间的内容(不包括后面的)赋值给num1Str，若输入1+2则获得1
            int strLen = inputStr.Count();
            Console.WriteLine($"strLen:{strLen},index:{index}");
            string num2Str = inputStr.Substring(index+1,strLen-index-1);//若输入1+2则获得2
            float num1 = float.Parse(num1Str);
            float num2 = float.Parse(num2Str);
            Console.WriteLine($"num1:{num1}, num2:{num2}");
            float result = func(num1, num2);
            Console.WriteLine($"{inputStr}的计算结果：{result}");
        }
    }
    public class CalcInfo
    {
        public string tag;
        public Func<float, float, float> func;
        public CalcInfo(string tag, Func<float, float, float> func)
        {
            this.tag = tag;
            this.func = func;
        }
    }

}
//
//5+6
//strLen:3,index:1
//num1:5, num2:6
//5+6的计算结果：11