import java.util.Arrays;

/**

* Demonstrates uses of arrays.

*/

public class ArrayExamples {

/**

* Example code from Chapter 7.

*/

public static void main(String[] args) {

int size = 10;

int[] counts = new int[4];

double[] values = new double[size];

counts[0] = 7;

counts[1] = counts[0] * 2;

counts[2]++;

counts[3] -= 60;

// traversal with a while loop

int j = 0;

while (j < 4) {

System.out.println(counts[j]);

j++;

}

// traversal with a for loop

for (int i = 0; i < 4; i++) {

System.out.println(counts[i]);

}

// displaying arrays

int[] array = {1, 2, 3, 4};

printArray(array);

// printing an array as an object

System.out.println(array);

// printing with Arrays class

System.out.println(Arrays.toString(array));

// copying an array

double[] a = {1.0, 2.0, 3.0};

double[] b = new double[a.length];

for (int i = 0; i < a.length; i++) {

b[i] = a[i];

}

// copying with Arrays class

double[] c = Arrays.copyOf(a, a.length);

// traversing arrays

for (int i = 0; i < a.length; i++) {

a[i] *= a[i];

}

// search

int index = search(a, 2.0);

System.out.println("index = " + index);

// reduce

double total = sum(a);

System.out.println("total = " + total);

}

/**

* Prints the elements of an array.

*/

public static void printArray(int[] a) {

System.out.print("{" + a[0]);

for (int i = 1; i < a.length; i++) {

System.out.print(", " + a[i]);

}

System.out.println("}");

}

/**

* Returns the index of the target in the array, or -1 if not found.

*/

public static int search(double[] array, double target) {

for (int i = 0; i < array.length; i++) {

if (array[i] == target) {

return i;

}

}

return -1; // not found

}

/**

* Returns the total of the elements in an array.

*/

public static double sum(double[] array) {

double total = 0.0;

for (int i = 0; i < array.length; i++) {

total += array[i];

}

return total;

}

}