// CSCI 1300 -- Practice for the Week 5 Programming Quiz
// File: lab-4.cxx
// Student Name:
// Complete the program as directed in the comments.  Test your work.
// Show your work to your TA.  Oh, yeah: and have fun!

#include <cstdlib>
#include <iomanip>
#include <iostream>
#include "graphics.h"
using namespace std;

int main( )
{
    // Please declare any variables that you need here.
    // Choose meaningful names and put a comment with each
    // variable indicating its purpose.
    int n;     // User's input
    int i, j;  // Loop control variables
    int sum;   // The sum for question 1.
    double z;  // User's input
    int count; // Number of times we cut z in half
    int x, y;  // Pixel coordinates
    
    // 1. Write a bit of C++ code that asks the user to type
    //    a positive integer n.  The program then uses a loop
    //    to compute the sum 1+2+3+4+...n.  This sum is then
    //    printed.

    // Michael's Solution:
    cout << "Please type a positive integer: ";
    cin >> n;
    sum = 0;
    i = 1;
    while (i <= n)
    {
	sum = sum + i;
	++i;
    }
    cout << "The sum is " << sum << endl;
    
    // Or as a for-loop:
    cout << "Please type a positive integer: ";
    cin >> n;
    sum = 0;
    for (i = 0; i <= n; ++i)
    {
	sum = sum + i;
    }
    cout << "The sum is " << sum << endl;
    

    // 2. Write a piece of code that asks the user to type any
    //    double z that is >= 1.0.  The program then uses a loop to
    //    determine how many times z can be cut in half before
    //    the value drops to 1.0 or less.  This number is then
    //    printed (it is approximately log base 2 of z).

    // Michael's solution:
    cout << "Please type a number >= 1.0: ";
    cin >> z;
    count = 0;
    while (z >= 1.0)
    {
	z = z/2;
	++count;
    }
    cout << "The approx log base 2 is " << count << endl;

    // 3. Write a piece of code that prints a simple multiplication
    //    table.  The table should list i*j for every value of i
    //    and j from zero to 9.  The easiest solution uses
    //    two nested loops!

    // Michael's solution:
    // This could also be done with while-loops, but the for-loops
    // seem more natural to me.  Notice that I am printing a
    // heading across the top and down the left side:

    // Print the top heading:
    cout << "     0  1  2  3  4  5  6  7  8  9" << endl;
    cout << "__|------------------------------" << endl;

    // Each iteration of the i loop prints one row of the table:
    for (i = 0; i <= 9; ++i)
    {
	// Print the label on the left edge:
	cout << i << " |";

	// Each iteration of the j loop prints one i*j:
	for (j = 0; j <= 9; ++j)
	{
	    cout << setw(3) << i*j;
	}

	// Print the end of line number i:
	cout << endl;
    }
    
    // 4. Complete the C++ code using a pair of nested loops.
    initwindow(100, 100, "Lab Quiz");
    // Write code that colors all the pixels on the screen
    // using the following formula for a pixel at coordinates
    // x (in the range 0 to 99) and y (in the range 0 to 99):
    // If x < 50, then the compute the color for the point (x,y)
    // as COLOR(x,50-y,y).  If x >= 50, then compute the color for
    // the point (x,y) as COLOR(x,y-50,y). For each x and y, you
    // may call putpixel(x, y, ...) where the ... is the COLOR
    // formula shown above.

    for (x = 0; x < 100; ++x)
    {
	for (y = 0; y < 100; ++y)
	{
	    if (x < 50)
		putpixel(x, y, COLOR(x, 50-y, y));
	    else
		putpixel(x, y, COLOR(x, y-50, y));
	}
    }
    
    
    getch( );
    return EXIT_SUCCESS;
}