/* 
This program demonstrates basic methods on arrays. 

1. printing an array
2. computing the sum of all elements in an array
3. sequential search an array for a target

Laura Toma
csci 107
*/


public class ArrayBasicFun {
	
	static ReadStream r;

	public static void main (String args[]) {

		r = new ReadStream(); 
		
		int i, n;
		int[] a;  //declare a variable a that stores an array 
		
		
		System.out.print("Enter array size: ");
		n = r.readInt();
		r.readLine(); 

		//create an array of this size
		a = new int[n];
		//read the array from user
		i = 0; 
		while (i < a.length) {
			System.out.print("Enter element " + i + ": ");
			a[i] = r.readInt();
			r.readLine();
			i++;
		}

		//print the array to the user
		printArray(a); 

		//compute the sum of all elements in the array 
		int s; 
		s = sumArray(a); 
		System.out.print("The sum of all element in the array is: " + s);
		
		//ask for a target 
		int t; 
		System.out.print("Enter a target  to search: "); 
		t = r.readInt(); 
		r.readLine(); 

		int pos; 
		pos = searchArray(a, t); 
		if (pos == -1) 
			System.out.println("Target not found");			
		else System.out.println("Target found at pos " + pos);
		
		
	} //end of main
	



	/* argument: an array x. This method prints all the elements in x,
	 * in order  */
	public static void printArray(int[] x) {
		int k; 
		k = 0;
		System.out.print("The array is: ");
		while (k < x.length) {
			System.out.print(x[k] + " ");
			k++; 
		}
		System.out.println();
	} //end of printArray


	/* argument: an array x. This method sums all the elements in x,
	 * and returns the sum   */
	public static int sumArray(int[] x) {
		int i, sum; 
		i = 0;
		sum = 0;
		while (i < x.length) {
			sum = sum + x[i];
			i++;
		}
		return sum; 
	}//end of computeSum
		

	/* argument: an array x and a target. This method searches for
	 * target in the array x, and returns: if target is found, the
	 * position where it is found; -1 if not found;  */
	public static int searchArray(int[] x, int target) {
		int k = 0, found = -1;
		while (k < x.length) {
			if (x[k] == target) found = k; 
			k++;
		}
		return found; 
	}//end of searchArray


} // end of class