# Help with understanding what his algorithm does and how it comes up with the numbers

• October 1st, 2012, 03:09 PM
soldatik21
Help with understanding what his algorithm does and how it comes up with the numbers
Just starting to lean about algorithm and programming and professor gave us this question and told us to figure out what i does thanks for the help
Code:

```#include <cstdlib> #include <iostream> #include <cmath> using namespace std; int main( ) {   double a, x_old, x_new;   cout << "Enter a positive DECIMAL number => ";   cin >> a;   x_old = 1;   x_new = 0.5*( 1 + a );   while( fabs(x_old - x_new) >= 0.00005)   {     x_old = x_new;     x_new = 0.5*( x_old * x_old + a )/x_old;   }   cout << "\nThe value that you are seeking is " << x_new << endl;   cout << "Press the enter key to continue ...";   cin.get();   return 0; }```
• October 1st, 2012, 03:20 PM
Paul McKenzie
Re: Help with understanding what his algorithm does and how it comes up with the numb
Quote:

Originally Posted by soldatik21
Just starting to lean about algorithm and programming and professor gave us this question and told us to figure out what i does thanks for the help

Regards,

Paul McKenzie
• October 1st, 2012, 03:23 PM
GCDEF
Re: Help with understanding what his algorithm does and how it comes up with the numb
Quote:

Originally Posted by soldatik21
Just starting to lean about algorithm and programming and professor gave us this question and told us to figure out what i does thanks for the help

Then you should probably do what your professor asked you to do. This isn't the do my homework for me forum.
• October 2nd, 2012, 04:37 AM
cilu
Re: Help with understanding what his algorithm does and how it comes up with the numb
• October 2nd, 2012, 07:13 AM
Peter_B
Re: Help with understanding what his algorithm does and how it comes up with the numb
As a first step, ignore the actual code and just try running it. See what output you get for various input values. Then, try to guess what function the code is calculating (it should be fairly obvious).
Once you have an idea as to what function this code calculates, see if you can work out how it is doing it.