A command line calculator in C++

calculator.cpp

#include<iostream>
#include<cmath>

using namespace std;

int main()
{
	//-------defining variables and initializing them-------------    
	double num1, num2;
	char operation, redo;
	//--------Printing my name on screen----------------    
	cout << "Welcome to the calculater program v.1.0 written by Nitish Kumar Diwakar" << endl;
	cout << "***************************************************************" << endl;
	cout << endl << endl << endl;
	//--here do loop is used so that the program can be used more then one time
	//without exiting the run screen---------------------------    
	do
	{
		//----receiving the variables from input--------------         
		cout << " Please enter an operation which you like to calculate (+,-,*,/,s)";
		cout << "[s stands for swap]:";
		cin >> operation;
		cout << endl << endl;
		cout << " Please enter two numbers to apply your requested operation(";
		cout << operation << "):" << endl << "1st num:";
		cin >> num1;
		cout << "2nd num:";
		cin >> num2;
		cout << endl;
		//---used switch function so thet the operater can be decided------------  
		switch (operation)
		{
			//------calculating the requested equation for inputs------------- 
			//-------at the same time printing the results on screen-----------          
		case'+':
			cout << "The addition of two numbers (" << num1 << "," << num2 << "):";
			cout << num1 + num2 << endl;
			break;
		case'-':
			cout << "The substraction of two numbers (" << num1 << "," << num2 << "):";
			cout << num1 - num2 << endl;
			break;
		case'*':
			cout << "The multiplication of two numbers (" << num1 << "," << num2 << "):";
			cout << num1*num2 << endl;
			break;
		case'/':
			cout << "The division of two numbers (" << num1 << "," << num2 << "):";
			if (num2 == 0)
			{
				cout << "not valid" << endl;
			}
			cout << (num1 / num2) << endl;
			break;
		case's':
			cout << "The swap of two numbers (" << num1 << "," << num2 << "):";
			swap(num1, num2);
			cout << "1stnumber=" << num1 << "and 2nd number=" << num2 << endl << endl;
			break;
		default:
			cout << "unknown command" << endl;

		}
		//----now once again the program will ask the user if want to continue or not          
		cout << "enter y or Y to continue:";
		cin >> redo;
		cout << endl << endl;
	} while (redo == 'y' || redo == 'Y');

	// system("pause");
  // uncomment above line if your are on windows
	return 0;

}