如何从c＃中输入的字符串（a + b）获取运算符类型？

Question

For example If the user gives input as a + b, process should be done as adding two variables that has been already declared as int a, int b

int a = 7;
int b = 8;
string formula = console.readline();

this is where I need Help if the user types a + b as formula we should addition on that a and b, User can use any binary operator, formula should get that operator from user input, Please help

Answer 1

You try to evaluate the math expression. I suggest to use NCalc

NCalc is a mathematical expressions evaluator in .NET. NCalc can parse any expression and evaluate the result, including static or dynamic parameters and custom functions.

• NCalc - Mathematical Expressions Evaluator for .NET

Answer 2

You could do like this:

int a = 7;
int b = 8;
string formula = "a+b";
formula=formula.Replace("a",a.ToString()).Replace("b",b.ToString());

var calc = new System.Data.DataTable();
Console.WriteLine(calc.Compute(formula, ""));

Answer 3

Made this a while ago to evaluate expressions like this

private static double Calc(string expression)
{
    try
    {
        var table = new System.Data.DataTable();
        table.Columns.Add("expression", string.Empty.GetType(), expression);
        System.Data.DataRow row = table.NewRow();
        table.Rows.Add(row);
        return double.Parse((string)row["expression"]);
    }
    catch (Exception)
    {
        return 0;
    }
}

Answer 4

This code allows the user to enter two numbers and the operator he or she wants

Console.WriteLine("Please enter the first number");
            int a = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the operator you want to use");
            string c = Console.ReadLine() ;

            Console.WriteLine("Enter the last number");
            int b = int.Parse(Console.ReadLine());

            string formula = "acb";
            formula = formula.Replace("a", a.ToString()).Replace("b", b.ToString()).Replace("c", c.ToString());

            var calc = new System.Data.DataTable();
            Console.WriteLine(calc.Compute(formula, ""));