C++ Tutorial in Linux

An introduction to C++, is very beneficial to the research group. I have written these
tutorials so programming resources are available. In this section I will write a little more about programming and give an example that will enable you to work, and learn c++ programming. In any programming language we always get an structure to how the program is build onto. One example of this is how we by in building a source code,  what does it take to have a program. Here is program structure that shows how a program works.



The problem that we have is the following.
You want to find the roots of a quadratic equation, given that, the standard equation for a quadratic equation is
Ax^2+Bx+C=0.

We we want to start design a program that would find the solutions to the quadratic equations,  because what we want to do is find a good solution based on our knowledge of quadratic equations.
 
Here is brief of how to configurate your Unix or Linux machine, depeninng from what you are working from.

I am particular working from the webster server.
If you are at teminal, make a directory that you can save all your work on: type
>mkdir practice
>cd practice
> emacs -nw quadratic_roots.cpp
My screen shot looks like this.
Type the following code in this file:

//******************************************************************
//Quadratic Root Finder: This program finds the roots of any
//quadratic equation. Using the equation x=-b+or-sqrt(b^2-4*a*c)/2*a
//******************************************************************
//Header Files
#include<iostream>
#include<cmath>

using namespace std;

int main()
{
  //declare variables
  int a=0, b=0, c=0;
  double discriminant=0, x_1=0, x_2=0;

  cout<<"Enter a, b, and c.";
  cin>>a>>b>>c;

  //Calculations
  discriminant = b*b-4*a*c;

  if (discriminant > 0)
    x_1=((-b)+sqrt(discriminant))/(2*a);
  x_2=((-b)-sqrt(discriminant))/(2*a);
  cout<<"The two real roots are "<<x_1<<" and "<<x_2<<" ."<<endl;

  if (discriminant < 0)
  cout<<"The roots are complex."<<endl;

  else if (discriminant == 0)
    x_1=(-b)/(2*a);
  cout<<"The only root is "<<x_1<<endl;

  return 0;
    }

*Note you can also copy and paste it in your file. To compile this file what we need to do is the following: In the prompth. Type the following comand.

>g++ quadratic_roots.cpp -o quadratic_roots.exe

What this command does is compiles the file quadratic_roots.cpp and turns that in an exacutable file. To execute the file, type what is shown below:
>./quadratic_roots.exe

It should run just fine. Even though we might find some problems trying to understand what it is doing.
Things you have learn:
1. Edit a new c++ file
2. Compile a c++ file and execute it.