I feel I am so stupid. I don't know what wrong in my programe code. I know I make a very silly mistake. Can you help me to make this programe running? Thank you very much!
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using System;

namespace Math
{
    class MathTest
    {
        public double add(double num1, double num2)
        {
             return (num1 + num2);
        }
        public double sub(double num1, double num2)
        {
            return (num1 - num2);
        }
        public double mul(double num1, double num2)
        {
            return (num1 * num2);
        }
        public double div(double num1, double num2)
        {
            return (num1 - num2);
        }
        static void Main(string[] args)
        {
            double firstNumber, secondNumber;
            Console.WriteLine("Please input your first number: ");
            firstNumber = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("Please input your second number: ");
            secondNumber = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("{0} + {1} = {2}", firstNumber, secondNumber, add(firstNumber, secondNumber));
            Console.WriteLine("{0} - {1} = {2}", firstNumber, secondNumber, sub(firstNumber, secondNumber));
            Console.WriteLine("{0} * {1} = {2}", firstNumber, secondNumber, mul(firstNumber, secondNumber));
            Console.WriteLine("{0} / {1} = {2}", firstNumber, secondNumber, div(firstNumber, secondNumber));
        }
    }
}

Looks like your div() function doesn't divide numbers, it subtracts them.


Take care,

Nik
http://www.bigaction.org/