/*
This file contains the source code to the lab items 1 to the system software. 
Task: Variant ?10 No one-dimensional array of positive real numbers. 
Convert the array as follows: first reset the minimum element, then the maximum of the other, 
then the minimum of the other, etc. as long as there will be a single element. 
Display the value and index the remaining elements.

Roman Kozar & Valery Zhezhel - All rights reserved. Copyright - 2015. 06March2015
*/

//constants
#define true 1 
#define elem 100

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <time.h>

//prototypes of the functions
void inputOfArray();
void inputRandom(); 
void inputKeyboard();
void algorithmExec(); 
void outputOfArray();

float intInput(int);
 
int minSearch(); 
int maxSearch(); 
int mainMenu(); 

//main array
float mainArray[elem];
int number=0;

void main() 
{
	char ch[2];
	int compare;	

	while(true) 
	{

		printf("Input the number of elements of the array (from 1 to %d):\n",elem);	
		//compareing variable
		compare=scanf("%3d%1[^\n]", &number, ch);
		//clearing buffer
		fflush(stdin);
		if(compare!=1)
		{ 
				printf("Error!\n");
				continue;
		}     
		if(number > elem || number < 0)			
			printf("\nEnter retry!\n");
		else 
		{
			break;
		}
		printf("\n");
	}
	printf("\nElements in the array.\n");
	printf("\n");

	while(true) 
	{			
		//menu items
		switch(mainMenu()) 
		{
			case 1:
				inputRandom();
				break;
			case 2:
				inputKeyboard(); 
					break;
			case 3:
				outputOfArray();
				break;
			case 4:
				algorithmExec();
				break;
			case 5:
				return;
			default: 
				printf("Error of the input. Try again.\n"); 
				break;
		}
		printf("\nPlease, press any key to continue.");
				/*
				returns the next character read from the console, 
				but does not display this symbol on the screen.
				*/
		getch();
		//clean the screen 
		system("cls");
	}
}

//function of main menu
int mainMenu() 
{
	int solution, compare;
	char chSymbol[2];

	printf( "Main Menu:\n1. Input the array with random.\n2. Input the array with keyboard\n3. Output the array.\n4. Run the task.\n5. Exit\n" );

	while(true) 
	{
		printf("Your choise:\n ");
		compare=scanf("%2d%1[^\n]", &solution, chSymbol);
		//clearing buffer
		fflush(stdin);
        if(compare != 1)
		{ 
			printf("Error!\n");
			continue;
		}	
		if(solution > 5 || solution < 0)			
			printf( "\nEnter retry!\n" );
		else
			break;
		printf("\n");
	}
	return solution;
}

//Directly to the algorithm
void algorithmExec() 
{	
	//count - counter, coordinate is the position of the element
	int count=0, coordinate;
	while(count!=number-1) 
	{
		coordinate=minSearch();
		mainArray[coordinate]=0; 
		count++;
		if(count!=number-1) 
		{
			coordinate=maxSearch();
			mainArray[coordinate]=0;
			count++;
		}
		if(count==number-1) 
			coordinate = maxSearch();
	}
	outputOfArray();
	//output the results
	printf("\nElement: %f; Position of the element: %d\n",mainArray[coordinate], coordinate);
}

//search min element
int minSearch() 
{
	int indicator=0;

	while(mainArray[indicator] == 0) 
		indicator++;

	double min=mainArray[indicator];
	int imin=indicator;

			for(int count=indicator; count < number; count++) 
			{
				if(mainArray[count]<min && mainArray[count]) 
				{
					min=mainArray[count];
					imin=count;
				}
			}
	return imin;
}

//search max element
int maxSearch()
{
	double max = mainArray[0]; 
	int imax=0;

	for(int count=0; count < number; count++) 
	{
		if(mainArray[count]>max && mainArray[count]!=0) 
		{
			max = mainArray[count];
			imax=count;
		}
	}
	return imax;
}

//function of random filling
void inputRandom() 
{
	printf("\nRange fill with random numbers from 0.1 to 1000.\n");
	//randome filling part
	srand(time(0));

	for(int count=0; count < number; count++) 
	{
		mainArray[count] = (float)rand() / RAND_MAX * (1000 - 0.1) + 0.1;
	}
	outputOfArray();
}

//function of filling by keyboard
void inputKeyboard() 
{

	printf("Enter the array elements :\n");

	for(int count=0; count < number; count++) 
	{
		printf( "Element number[%d]: ", count+1 );
		intInput(count);
	}
	outputOfArray();
}

//output of array
void outputOfArray() 
{
	printf("\nFinal output of array:\n");

	for(int count=0; count < number; count++) 
	{
		printf("%.2f  ", mainArray[count]);
	}
} 

float intInput(int count)
{
	char chSymbol[6];
	int compare;

	while(true) 
	{
		compare=scanf( "%3f%1[^\n]", &mainArray[count], chSymbol );

		//clearing buffer
		fflush(stdin);
        if(compare == 1)
		{ 
			return mainArray[count];
		}
		else
		{
			printf("Error!\n");
			printf("Element number[%d]: ", count+1);
			printf("\n");
		}
	}
}