#include <stdio.h>
#include <math.h> // USE "gcc array2.c -lm" to link in the math library
// #define MAX 100

const int MAX = 100;

void makeArray(int a[])
{
	int i;
	
	srand(time(0));
	for(i=0; i < MAX; i++) {
		a[i] = rand() % 1000;
	}
}

void printArray(int a[])
{
	int i;
	
	for(i=0; i < MAX; i++) {
		printf("%4d", a[i]);
		if (i % 10 == 9)
			printf("\n");
	}
}

void swapFirstLast(int a[])
{
	int temp;
	temp = a[0];
	a[0] = a[MAX-1];
	a[MAX-1] = temp;
}

int sumArray(int a[])
{
	int sum = 0;
	int i;

	for(i = 0; i < MAX; i++) {
		sum = sum + a[i];
	}

	return sum;
}

void printString(char str[])
{
	printf("%s\n", str);
}

int main()
{
	int arr[MAX];
	char str1[] = "hello world";
	char str2[80];
	int total;
	double squareroot;
   
	makeArray(arr);
    printArray(arr);

	printf("Hi, enter a string: ");
	scanf("%s", str2);
	printString(str1);
	printString(str2);

	swapFirstLast(arr);
	printArray(arr);
	total = sumArray(arr);
	
    printf("Sum = %d, sum/MAX=%f or as int:%d\n", 
				total, (double)total/MAX, total/MAX);	
	
    squareroot = sqrt(total);  // Use "gcc array2.c -lm" to link in math library

	printf("Square root = %lf\n", squareroot); 
	return 0;
}