Memoization(not memorization) is a programming technique often used in dynamic programming. In essence, it just means having your program remember previous calculations and reuse those results in similar calculations later. It's a rather simple technique and yet it can make a huge difference in efficiency.
Let's the common task of calculating Fibonacci numbers. Say that I need to output the first n Fibonacci numbers. Well the simplest approach is to use tree recursion:
Now although this solution is the easiest to formulate it is extremely inefficient. The reason why it is so inefficient, is because there is a huge amount of recalculation involved. Take fibonacci(6), which is to take the 6th term of Fibonacci. If we trace the recursive calls, we will see a structure similar to this:
f(6)
f(5) + f(4)
f(4) + f(3) + f(3) + f(2)
f(3) + f(2) + f(2) + f(1) + f(2) + f(1) + f(1) + f(0)
f(2) + f(1) + f(1) + f(0) + f(1) + f(0) + 1 + f(1) + f(0) + 1 + 1 + 0
f(1) + f(0) + 1 + 1 + 0 +... View In Full
In C, if you ever wanted to use strings, you would need to use a null-terminated array of characters. It was ugly, unsophisticated, and very susceptible to buffer overflows. C++ and it's STL gives you a much better solution; the string class.
Making a string is easy:
#include <string>
using namespace std;
string firstName("Oleksi");
string lastName;
lastName = "Derkatch";
Simple, as you can see. Strings keep track of their own size using the length() member:
string name("Oleksi");
name.length(); //Returns 6
name = "ma";
name.length(); //Returns 2
As you can see, changing the string value is simple as well. If you need to access individual characters of the string, you can treat the string as a character array in C. That is, you can easily do something like this:
string name("Jack");
for (int i(0); i < name.length(); ++i)
{
cout << name ;
}
C++ overloads the extracti... View In Full
The C++ STL library defines a vector class which gives you a pre-made generic vector. You can use it in the same way as you would a regular array, only a vector is safer to use and more sophisticated.
Creating one is simple:
#include <vector>
using namespace std;
vector<int> myVector;
You have now created a vector to hold integers. One of the best things about vectors is that memory for them is dynamically allocated. This is perfect for occasions when you do not know the exact number of elements you may need at compile time. Here's an example:
#include <vector>
using namespace std;
vector<int> myVector;
myVector.push_back(42);
myVector.push_back(34);
Note that I never explicitly tell the compiler how large my vector is. At this point in time, it contains 2 elements, but I can easily add another element to the back of the vector. If I need to get the number of elements in the vector, I can simply use the size()... View In Full
A small implementation of a generic Linked List in C#. Let me know if I'm making any C# faux pas. I'm still learning the language.
This list supports:
adding to the end
indexing
index lookup
re
Draws the Julia set. This option lets you customize colors and the specific set. You can even draw the Mandelbrot set. Experiment with the colors to see some really pretty fractals.
At a glance, everything looked good! I have never created a script like that with C#, so it was in some case new to me. But all the syntax looked good as I don't think .NET has any default classes for what you were trying to do.
Glad to hear it! I still think I might learn C++ though. Actually I think I will HAVE to since my Computer Engineering class does C++ programing and then on to machine code... oh boy. Fun stuff.
