// File: is.cxx
// First examples of functions that return boolean values
#include <cstdlib>
#include <iostream>
#include <graphics.h>
using namespace std;
const int S = 300;

//--------------------------------------------------------
// Function prototypes. In all these functions, ss is
// the size of an already open graphics screen

// Allow the user to select one of our functions:
int selection( );

// Returns true if n > 9000:
bool is_big(int n);

// Returns true if a <= b and b <= c:
bool is_in_order(int a, int b, int c);

// True if the graphics screen has at least one red pixel:
bool is_some_red(int ss);

// True if the graphics screen has all red pixels:
bool is_all_red(int ss);

// True if the graphics screen has all red pixels:
bool is_majority_red(int ss);

// Open a window with a certain probability of red pixels:
void open_window(int ss, double red_probability);
//--------------------------------------------------------

//--------------------------------------------------------
int main( )
{
    int n, a, b, c; // User input to test function
    double percentage; // User input to test function

    switch (selection( ))
    {
    case 1: // Test is_big
	cout << "Enter an integer: ";
	cin >> n;
	if (is_big(n))
	    cout << "That's bigger than 9000!" << endl;
	else
	    cout << "That's small." << endl;
	break;
	
    case 2: // Test is_in_order
	cout << "Enter three integers: ";
	cin >> a >> b >> c;
	if (is_in_order(a, b, c))
	    cout << "Nicely ordered!" << endl;
	else
	    cout << "Those are out of order." << endl;
	closegraph( );
	break;
	
    case 3: // Test is_some_red
	cout << "Enter the percentage of red for a screen: ";
	cin >> percentage;
	open_window(S, percentage);
	if (is_some_red(S))
	    cout << "There is some red!" << endl;
	else
	    cout << "Not a speck of red!" << endl;
	delay(5000);
	closegraph( );
	break;
	
    case 4: // Test is_all_red
	cout << "Enter the percentage of red for a screen: ";
	cin >> percentage;
	open_window(S, percentage);
	if (is_all_red(S))
	    cout << "That's all red!" << endl;
	else
	    cout << "Not all is red!" << endl;
	delay(5000);
	closegraph( );
	break;

    case 5: // Test is_majority_red
	cout << "Enter the percentage of red for a screen: ";
	cin >> percentage;
	open_window(S, percentage);
	if (is_majority_red(S))
	    cout << "That's mostly red!" << endl;
	else
	    cout << "That's not mostly red!" << endl;
	delay(5000);
	closegraph( );
	break;
    }

    return EXIT_SUCCESS;
}
//--------------------------------------------------------

//--------------------------------------------------------
bool is_big(int n)
{
    return (n > 9000);
}
//--------------------------------------------------------

//--------------------------------------------------------
bool is_in_order(int a, int b, int c)
{
    return (a <= b) && (b <= c);
}
//--------------------------------------------------------

//--------------------------------------------------------
bool is_some_red(int ss)
{
    int px, py;
    for (px = 0; px < ss; ++px)
    {
	for (py = 0; py < ss; ++py)
	{
	    if (getpixel(px, py) == RED)
	    {
		return true;
	    }
	}
    }
    return false;
}
//--------------------------------------------------------

//--------------------------------------------------------
bool is_all_red(int ss)
{
    return true;
}
//--------------------------------------------------------

//--------------------------------------------------------
bool is_majority_red(int ss)
{
    return true;
}
//--------------------------------------------------------

//--------------------------------------------------------
void open_window(int ss, double red_probability)
{
    initwindow(ss, ss);
    int px, py;
    for (px = 0; px < ss; ++px)
    {
	for (py = 0; py < ss; ++py)
	{
	    if (double(rand())/RAND_MAX < red_probability)
	    {
		putpixel(px, py, RED);
	    }
	}
    }
    
}
//--------------------------------------------------------

//--------------------------------------------------------
int selection( )
{
    int answer;
    
    cout << "Please select one of these options: " << endl;
    cout << "  1: is_big(int n)" << endl;
    cout << "  2: is_in_order(int a, int b, int c)" << endl;
    cout << "  3: is_some_red(int ss)" << endl;
    cout << "  4: is_all_red(int ss)" << endl;
    cout << "  5: is_majority_red(int ss)" << endl;
    cout << "Your selection: ";

    cin >> answer;
    return answer;
}
//--------------------------------------------------------