My buddy and I finally acomplish our project for our TC101 class.

Well, basically, our program had to do the following:

“You will create a command-line program that uses two-dimensional arrays or matrices to process images. You cannot simply call graphics libraries to manipulate the images directly but must implement the functions with your own algorithms. The input to each operation is an image (you choose to support any of JPEG, PNG) and the output is the modified image. The idea is to have a final project which shows your mastery of the topics in this course”.

I was really hard to acomplish but Eduardo and I worked together and we made it!

The user is able to type in the name of the file (a picture) and the program will process the image outputting a different file than the first one.

There is a huge code!

It looks like this:

#include <Magick++.h>
#include <iostream>
#include <cmath>
using namespace std;
using namespace Magick;

void grayscale (string in, string out){
  Image image;
  image.read( in );
  int x = image.rows();
  int y = image.columns();
  Color image_array [x] [y];
  Color original;
  Color graysc;
  int col;


  for (int i=0; i < x; i++){                    
    for (int u = 0; u < y; u++){               
      original = image.pixelColor(u,i); 
      image_array [i][u] = original;
      col = (original.redQuantum() + original.greenQuantum() + original.blueQuantum()) / 3;
      graysc.redQuantum(col);
      graysc.greenQuantum(col);
      graysc.blueQuantum(col);
      image_array [i] [u] = graysc;
      image.pixelColor(u, i, graysc);
    }
  }
  image.write( out );
}

void scale(string in, string out){
  Image image;
  image.read( in );

  int x = image.rows();
  int y = image.columns();
  int xf = x/2;
  int yf = y/2;
  Image image2( Geometry(yf, xf), Color(MaxRGB, MaxRGB, MaxRGB, 0));
  Color image_array [x] [y];
  Color image_array2 [xf] [yf];
  Color pixel1, pixel2, pixel3, pixel4, pixel5;
  int red,blue,green;
  Color newRGB, newRGB2;

  for (int i=0; i < x; i++){
        for (int u = 0; u < y; u++){
              pixel1 = image.pixelColor(u,i);
              image_array [i][u] = pixel1;
        }
  }

  for (int i=0; i < x; i = i+2){
       for (int u = 0; u < y; u = u+2){
       	     int x2 = i/2;
       	     int y2 = u/2;
             pixel2 = image_array [i] [u];
             pixel3 = image_array [i+1] [u];
             pixel4 = image_array [i] [u+1];
             pixel5 = image_array [i+1] [u+1];
             red = (pixel2.redQuantum() + pixel3.redQuantum() + pixel4.redQuantum() + pixel5.redQuantum())/4;
             blue = (pixel2.blueQuantum() + pixel3.blueQuantum() + pixel4.blueQuantum() + pixel5.blueQuantum())/4;
             green = (pixel2.greenQuantum() + pixel3.greenQuantum() + pixel4.greenQuantum() + pixel5.greenQuantum())/4;
             newRGB.redQuantum(red);
             newRGB.greenQuantum(green);
             newRGB.blueQuantum(blue);
             image_array2 [x2] [y2] = newRGB;
       }
  }

  for (int i=0; i < xf; i++){
       for (int u = 0; u < yf; u++){
             newRGB2 =image_array2 [i] [u];
             image2.pixelColor(u, i, newRGB2);
       }
  }

 image2.write( out );
}

int main(int argc,char **argv)
{
  InitializeMagick(*argv);

  try {
 string im;
 string out;
 int ans;
 cout << "Write your file name: ";
 cin >> im;
 cout<< "Write the name of your output file: ";
 cin>>out;
 cout<<"What do you wanna do?"<<endl<<"1. Grayscale."<<endl<<"2. Scale (1/2)."<<endl;
 cin>>ans;

while (ans != 1 && ans != 2){
  cout<<"Try again please: ";
  cin>>ans;}
if(ans == 1){
 grayscale(im, out);}
 if (ans == 2){
 scale(im, out);
}
}
  catch( Exception &error_ )
    {
      cout << "Caught exception: " << error_.what() << endl;
      return 1;
    }
  return 0;
//// c++ -O2 -o prog prog.cpp `Magick++-config --cppflags --cxxflags --ldflags --libs`
}

There is also a Repository made it in Github and that’s were our teacher is going to check it out.

Any question feel completely free to ask.

Thank you guys for everything.

-The Admin.

Instead of declaring individual variables, such as number0, number1, …, and number99, you declare one array variable such as numbers and use numbers[0], numbers[1], and …, numbers[99] to represent individual variables. A specific element in an array is accessed by an index.

All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element.

Declaring Arrays:

To declare an array in C++, the programmer specifies the type of the elements and the number of elements required by an array as follows:

type arrayName [ arraySize];

This is called a single-dimension array. The arraySize must be an integer constant greater than zero and type can be any valid C++ data type. For example, to declare a 10-element array called balance of type double, use this statement:

double balance[10];

Initializing Arrays:

You can initialize C++ array elements either one by one or using a single statement as follows:

double balance[5] = {1000.0, 2.0, 3.4, 17.0, 50.0};

The number of values between braces { } cannot be larger than the number of elements that we declare for the array between square brackets [ ]. Following is an example to assign a single element of the array:

If you omit the size of the array, an array just big enough to hold the initialization is created. Therefore, if you write:

double balance[] = {1000.0, 2.0, 3.4, 17.0, 50.0};

You will create exactly the same array as you did in the previous example.

-The Admin.

What is Scilab ?

Scilab is free and open source software for numerical computation providing a powerful computing environment for engineering and scientific applications.

What does Scilab do ?

Scilab includes hundreds of mathematical functions. It has a high level programming language allowing access to advanced data structures, 2-D and 3-D graphical functions.

A large number of functionalities is included in Scilab:

• Maths & Simulation
  For usual engineering and science applications including mathematical operations and data analysis. 
• 2-D & 3-D Visualization
  Graphics functions to visualize, annotate and export data and many ways to create and customize various types of plots and charts.
• Optimization
  Algorithms to solve constrained and unconstrained continuous and discrete optimization problems.
• Statistics
  Tools to perform data analysis and modeling
• Control System Design & Analysis
  Standard algorithms and tools for control system study
• Signal Processing
  Visualize, analyze and filter signals in time and frequency domains.
• Application Development
  Increase Scilab native functionalities and manage data exchanges with external tools.
• Xcos – Hybrid dynamic systems modeler and simulator
  Modeling mechanical systems, hydraulic circuits, control systems…

Where can I get this Software?

As always, just clic on BATMAN.

And also, very important! You will need a beginers guide that will help you out in your familiarization with the program. To download the guide just clic on ROBIN.

Here is a video with basic operations made in Scilab.

-The Admin.

Vector Constructors.

The available constructors for a vector are given by:

1	vector<int> testVector;
2	vector<long> testVector(10);
3	vector<float> testVector(5,1.0);

The first syntax declares an empty vector capable of storing the integer datatype. The second declares a vector with storage space for 10 long integers, each of which is initialized to the default value for the type. The final line declares a vector with storage for 5 floats, and initializes each of their values to 1.0. Any valid type can be used for any of the constructors.

There is also a copy constructor for the std::vector class. The following code creates a vectors of integers with 10 copies of the number 5, and duplicates the vector into a new one using the copy constructor:

01	#include <iostream>
02	#include <vector>
03	 
04	using namespace std;
05	 
06	int main(int argc, char** argv) {
07	     
08	    vector<int> vectorOne(10,5);
09	     
10	    vector<int> vectorTwo(vectorOne);
11	     
12	    return EXIT_SUCCESS;
13	}

Accessing Elements of a Vector.

There are a number of ways to access the elements of a vector. For the moment, I will focus on two of them, one safe and one unsafe. And as a reminder, C++ vectors (and other STL containers), like raw C/C++ arrays, are accessed with indices starting at zero. This means that the first element is at position 0 in the vector, and the last element is at position (number of elements)-1.

The vector class contains a member function at() for accessing individual elements of a vector. This is the safe way of accessing elements, since attempting to access an element beyond the valid range will cause an exception to be thrown. However, the raw data stored in the vector can still be accessed using the usual [] operator, just like in a raw array. Unfortunately, just like with a raw array of data, overrunning the end of the vector using the [] operator can cause weird and unexpected things to occur, such as program crashes or unexpected results. It may also return garbage data that follows the meaningful data of the vector, which has the potential to be disastrous if it is used in subsequent operations. The following two code snippets demonstrate each of these access methods:

Safe access version:

#include <iostream>
#include <vector>
using namespace std;
 

int main(int argc, char** argv) {
     
    /*  Initialize vector of 10 copies of the integer 5 */

    vector<int> vectorOne(10,5);
     
    /*  Display size of vector */

    cout << "Size of vector is " << vectorOne.size() << " elements." << endl;
     
    /*  run through the vector and display each element, using size() to determine index boundary */

    for (long index=0; index<(long)vectorOne.size(); ++index) {

        cout << "Element " << index << ": " << vectorOne.at(index) << endl;
    }

    return EXIT_SUCCESS;
}

Unsafe access version

#include <iostream>
#include <vector>
 
using namespace std;

 
int main(int argc, char** argv) {
     

    /*  Initialize vector of 10 copies of the integer 5 */
    vector<int> vectorOne(10,5);
     

    /*  run through the vector and display each element, if possible */

    for (int index=0; index<20; ++index) {

        cout << vectorOne[index] << endl;

    }
    return EXIT_SUCCESS;
}

Sources:

http://www.cplusplus.com/reference/vector/vector/vector/

http://www.codeguru.com/cpp/cpp/cpp_mfc/stl/article.php/c4027/C-Tutorial-A-Beginners-Guide-to-stdvector-Part-1.htm

-The Admin.

switch (expression)
{
  case constant1:
     group-of-statements-1;
     break;
  case constant2:
     group-of-statements-2;
     break;
  .
  .
  .
  default:
     default-group-of-statements
}

Basically, what “Switch” actually does is to evaluate expression and checks if it is equivalent to constant1; if it is, it executes group-of-statements-1 until it finds the break statement. When it finds this break statement, the program jumps to the end of the entire switch statement (the closing brace).

If expression was not equal to constant1, it is then checked against constant2. If it is equal to this, it executes group-of-statements-2 until a break is found, when it jumps to the end of the switch. Finally, if the value of expression did not match any of the previously specified constants (there may be any number of these), the program executes the statements included after the default: label, if it exists (since it is optional). Both of the following code fragments have the same behavior, demonstrating the if-else equivalent of a switch statement:

switch (x) {

  case 1:

    cout << "x is 1";

    break;

  case 2:

    cout << "x is 2";

    break;

  default:

    cout << "value of x unknown";

  }

if (x == 1) {

cout << "x is 1";

}

else if (x == 2) {

cout << "x is 2";

}

else {

cout << "value of x unknown";

}

Here is a simple example of a code with a “Switch” Statement in it.

switch (x) {
  case 1:
  case 2:
  case 3:
    cout << "x is 1, 2 or 3";
    break;
  default:
    cout << "x is not 1, 2 nor 3";
  }

Sources:

http://en.cppreference.com/w/cpp/language/switch

http://www.cplusplus.com/doc/tutorial/control/#switch

-The Admin.

I checked out the introduction for beginners and I learned how to use it, it’s actually pretty simple to do the basic things and for the advanced stuff well, I will need more practise.

It is really a usefull tool that I thing will help a lot during my class of math and physics not only because it works as a calculator, but also it can print graphics and you can create your own programs writing the code lines inside the program! That’s awesome.

No doubt Scilab is an excellent tool and I can’t wait to keep practising and descovering new stuff in it.

-The Admin.

In this WSQ I had to calculate the e number of a value, here is the full instruction:

“In this assignment you will estimate the mathematical constant e. You should create a function called calculuate_e which receives one parameter called precision that should specify the number of decimal points of accuracy.”

This is the same question as the one that I solve in Quiz # 11, so the code is the following:

BATMAN.

And here is the picture of the program running.

Stay true!

-The Admin.

In this WSQ #13 we had to write a program which do the following:

“The function should receive a number and return floating point number. Obviously you should test your function, so create a main program that asks the user a value, calculates the square root and displays that.”

So I had to do some research and a really cool video in Youtube help me a lot! From the tutorial I just had to change double to float and put a “Cin” so the user could type in the number that he wants.

This is the tutorial that helped me out!

And as always, Clic on Batman to see my code!

Here is a screenshot of the program running:

Stay true!

-The Admin.

The first step was to be able to ask the user for the name os the file, so he  could type in the name and our program will look for it and process the image in order to change it.

That’s what we got so far and we are now working on the conversion of the pixels from color to B&W.

Hopefully everything will be ready before the deadline of November 25 at midnight.

Goodnight!

-The Admin.

Euclids Algorithm:

The Euclidean algorithm is based on the principle that the greatest common divisor of two numbers does not change if the larger number is replaced by its difference with the smaller number. For example, 21 is the GCD of 252 and 105 (252 = 21 × 12 and 105 = 21 × 5), and the same number 21 is also the GCD of 105 and 147 = 252 − 105.

Here is the code of the program.

#include <iostream>
using namespace std;

int gcd(int a, int b){//Making the function
	int g=a;
	int h,l;
	int f=2;
	if(a==0){
		return a;
	}
		while(g>0){//Doing a loop
		if(g==0){
			goto exit;
		}
		g=a%b;
		a=b;
		b=g;
		}
	if (l=1000){
	exit:
	g=a;
	}
	return g;
}

int main(){
int a, b;
cout<<"Please introduce the first number"<<endl;
cin>>a;
cout<<"Please introduce the second number"<<endl;
cin>>b;
cout<<endl;

cout<<"Your Greatest Common Divisor is: "<<gcd(a,b)<<endl;

return 0;
}

Also, Here is the link to the code in Github: BATMAN.

And of course, as always, the picture of the execution of the program on Cygwin.

-The Admin.