CSCI 261 - Programming Concepts (C++)

This assignment is due by Tuesday, April 3, 2017 11:59pm.

This assignment will continue right where Assignment 08 left off. Recall that your solution to A08 wrote out to a file the frequency of each letter in the Alice in Wonderland text. Well now we are going to graph those frequencies in a much easier to read format.

You will need to begin with the SFML Template once again and rename the project to be A09. Begin by reading in the contents of your letter frequency file into an array that stores the frequency of each letter. You should once again be using an array of size 26.

Ready for the GUI part of your homework? Fasten your seat belt and enjoy the ride! In this part you will draw a window that shows a bar for each letter of the alphabet, with its height proportional to the corresponding frequency. The bar that corresponds to the most frequent letter should be painted with a different color. The bar that corresponds to the least frequent letter should be painted with yet a third color. Each bar is identified by its correspondent letter with a label at the bottom.

To draw the bars of the GUI you will use the RectangleShape object called bar. For each letter you should draw a bar with a height proportional to the letter frequency. All bars should have the same width, can you guess what it is?

To set the bar's size you should use the object's setSize function. In a similar way, to set the bar's position you should use the object's setPosition function. The following example shows how to change the size of the bar object using the values width=20 and height=100 AND the position of the bar object using the values x=80 and y=250. Note that because you will be drawing a bar for each letter using a loop, you should use variables like width, height, x, and y to set the bar's properties accordingly.

To set the bar's color you should use the setFillColor function. Remember to set a different color to the bar that corresponds to the most frequent letter. After setting the bar's size, position, and color, you should draw the object on your window using the window's draw function, illustrated in the code that follows.

To draw the text labels of the bars, you first need to load the particular font you will use (we include arial.ttf in the data directory of the SFML template) and then use the Text object (perhaps called text). To set the text's position you should use the object's setPosition function in a similar way as you did for the RectangleShape object. To set the text's label you should use the object's setString function. This function expects a string and what you have for each letter is a char. The following snippet of code illustrates how to set the position of the text object using the values x=80 and y=250 with a text label based on character 'a' (assuming you have a charToString function available). Finally, to actually draw the text object on your window you should use the draw function.

The function charToString() is as simple as:

string charToString( char c ) {
    string s;
    s.push_back( c );
    return s;
}

Use a loop to traverse your frequencies array. At each iteration, draw a bar and a text label for the correspondent letter. Let's say that you are using a variable named height to compute the height of the 'to be drawn' bar. You can then use the height of your window (i.e., a HEIGHT constant) divided by the frequency of the most frequent letter as a scaling factor to compute the height of each bar. After the bar's height is computed, determining its y coordinate is a piece of cake: just subtract the bar's height from the window HEIGHT.

Your submission will be graded according to the following rubric.

Always, always, ALWAYS update the header comments at the top of your main.cpp file. And if you ever get stuck, remember that there is LOTS of help available.

In summary, for homework due on Tuesday, April 3 follow these specific steps:

This assignment is due by Tuesday, April 3, 2017 11:59pm.