Check out example codes for "c# calculator". It will help you in understanding the concepts better.

Code Example 1

``````using System;

namespace Calculator
{
class Calculator
{
public static double DoOperation(double num1, double num2, string op)
{
double result = double.NaN; // Default value is "not-a-number" which we use if an operation, such as division, could result in an error.

// Use a switch statement to do the math.
switch (op)
{
case "a":
result = num1 + num2;
break;
case "s":
result = num1 - num2;
break;
case "m":
result = num1 * num2;
break;
case "d":
// Ask the user to enter a non-zero divisor.
if (num2 != 0)
{
result = num1 / num2;
}
break;
// Return text for an incorrect option entry.
default:
break;
}
return result;
}
}

class Program
{
static void Main(string[] args)
{
bool endApp = false;
// Display title as the C# console calculator app.
Console.WriteLine("Console Calculator in C#\r");
Console.WriteLine("------------------------\n");

while (!endApp)
{
// Declare variables and set to empty.
string numInput1 = "";
string numInput2 = "";
double result = 0;

// Ask the user to type the first number.
Console.Write("Type a number, and then press Enter: ");

double cleanNum1 = 0;
while (!double.TryParse(numInput1, out cleanNum1))
{
Console.Write("This is not valid input. Please enter an integer value: ");
}

// Ask the user to type the second number.
Console.Write("Type another number, and then press Enter: ");

double cleanNum2 = 0;
while (!double.TryParse(numInput2, out cleanNum2))
{
Console.Write("This is not valid input. Please enter an integer value: ");
}

// Ask the user to choose an operator.
Console.WriteLine("Choose an operator from the following list:");
Console.WriteLine("\ts - Subtract");
Console.WriteLine("\tm - Multiply");
Console.WriteLine("\td - Divide");

try
{
result = Calculator.DoOperation(cleanNum1, cleanNum2, op);
if (double.IsNaN(result))
{
Console.WriteLine("This operation will result in a mathematical error.\n");
}
}
catch (Exception e)
{
Console.WriteLine("Oh no! An exception occurred trying to do the math.\n - Details: " + e.Message);
}

Console.WriteLine("------------------------\n");

// Wait for the user to respond before closing.
Console.Write("Press 'n' and Enter to close the app, or press any other key and Enter to continue: ");
if (Console.ReadLine() == "n") endApp = true;

Console.WriteLine("\n"); // Friendly linespacing.
}
return;
}
}
}``````

Learn ReactJs, React Native from akashmittal.com