main.c

// Milan Vit - R09387
// Test c. 1, 1. 11. 2010

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

	// Task 1
#define VOLUME(r, h) ((3.14159265) * (r) * (r) * (h))

int getLength () {
	int length;
	
	printf ("Array length: ");
	scanf ("%d", &length);
	
	return (length);
}

void fillArray (int array[], int length, int down, int top) {
	int i;
	
	for (i = 0; i < length; i++) {
		array[i] = down;
		down++;
		
		if (down == (top + 1)) {
			break;
		}
	}
}

void printArray (int array[], int length) {
	int i;
	
	for (i = 0; i < length; i++) {
		printf ("%d", array[i]);
		
		if ((i + 1) != length) {
			printf (", ");
		} else {
			printf (".\n");
		}

	}
}

int oddNumbersInArray (int array[], int length) {
	int i, oddNumbers = 0;
	
	for (i = 0; i < length; i++) {
		if ((array[i] % 2) == 1) {
			oddNumbers++;
		}
	}
	
	return (oddNumbers);
}

void primeNumber (int number) {
	int i, primeNumber = 0;	// let's suppose it is prime number
	
	if ((number <= 1) || ((number % 2) == 0)) {
		if (number == 2) {
			primeNumber = 0;
		} else {
			primeNumber = 1;
		}
	} else {
		for (i = 3; i <= sqrt (number); i += 2) {
			if ((number % i) == 0) {
				primeNumber = 1;
			}
		}
	}
	
	if (primeNumber == 0) {
		printf ("Number %d is prime number.\n", number);
	} else {
		printf ("Number %d is not prime number.\n", number);
	}
}

float lineSum (int number) {
	int i, add = 0;	// first operation is addition
	float sum = 1;
	
	for (i = 2; i <= number; i++) {
		if (add == 0) {
			sum += 1.0 / (float) i;
			add = 1;
		} else {
			sum -= 1.0 / (float) i;
			add = 0;
		}
	}
	
	return (sum);
}

void shuffleArray (int array[], int arrayLength) {
	int i, j;
	int tempArray[arrayLength];
	
		// Let's copy everything to temporary array first
	for (i = 0; i < arrayLength; i++) {
		tempArray[i] = array[i];
	}
	
		// Now move the hell back
	for (i = 0, j = arrayLength - 1; i < arrayLength; i++, j--) {
		array[i] = tempArray[j];
	}
}

int main (int argc, const char *argv[]) {
	float sum;
	int length, oddNumbers;
	int shufflingArray[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
	int *array;
	
		// Task 1
	length = getLength ();
	if ((array = (int *) malloc (length * sizeof (int))) == NULL) {
		printf ("Memory allocation error!");
		return (1);
	}
	
		// Task 2
	fillArray (array, length, 6, 10);
	printArray (array, length);
	
		// Task 3
	oddNumbers = oddNumbersInArray (array, length);
	printf ("%d odd number(s) in array.\n", oddNumbers);
	
		// Task 4
	printf ("Cylinder volume: %fj^3.\n", VOLUME (3, 4));
	
		// Task 5
	primeNumber (1);
	primeNumber (2);
	primeNumber (3);
	primeNumber (4);
	primeNumber (5);
	primeNumber (6);
	
		// Task 6
	sum = lineSum (7);
	printf ("Sum is %f.\n", sum);
	
		// Task 7
	shuffleArray (shufflingArray, 10);
	printArray (shufflingArray, 10);
	
		// Task 1
	free (array);
}