import java.util.Scanner;

class Sep25 {
	public static void main(String[] args) {


		int i = 0; 	// initializing i
		while(i < 10) {   // checking bounds 
			System.out.printf("%d ", i);
			i++;	// incrementing i
		}
		System.out.println();

		// equivalent code using for-loop

		for(int j = 0; j < 10; j++) {
			System.out.printf("%d ", j);
		}
		System.out.println();


		// arrays

		// an array is a datastructure that can hold
		// a predetermined number of instances of any
		// type

		int[] array = new int[10];  // hard coding size of array

		System.out.print("Enter number of quiz scores: ");
	
		Scanner kb = new Scanner(System.in);
		int len = kb.nextInt();

		int[] quizScores = new int[len];
		System.out.println("quiz scores: " + quizScores);

		for(int k = 0; k < len; k++) {
			System.out.printf("%d ", quizScores[k]);
		}
		System.out.println();

		// print out integer at index 5
		System.out.println("elm at index 5: " + quizScores[5]);

		// declare a variable and intialize it to the value 
		// that is stored at index 3

		int elmAt3 = quizScores[3];
		int elmAt9 = quizScores[9];

		//int elmAt11 = quizScores[11];  // bad!
		// int elmAtNegative1 = quizScores[-1];  // bad!

		// change value of first element in array to 7
		quizScores[0] = 7;

		for(int k = 0; k < len; k++) {
			System.out.printf("%d ", quizScores[k]);
		}
		System.out.println();

		// set all elements in the array to -1

		for(int k = 0; k < len; k++) {
			quizScores[k] = -1;
		}

		for(int k = 0; k < len; k++) {
			System.out.printf("%d ", quizScores[k]);
		}
		System.out.println();

		
		for(int k = 0; k < len; k++) {
			System.out.print("Enter quiz score: ");
			quizScores[k] = kb.nextInt();	
		}
		System.out.println();


		for(int k = 0; k < len; k++) {
			System.out.printf("%d ", quizScores[k]);
		}
		System.out.println();

		System.out.print("Enter 10 quiz score: ");
		for(int k = 0; k < len; k++) {
			quizScores[k] = kb.nextInt();	
		}
		System.out.println();
		

		for(int k = 0; k < len; k++) {
			System.out.printf("%d ", quizScores[k]);
		}
		System.out.println();

	}
}