Arrays HW Post
Arrays HW post for AP CSA
Notes:
- An array is a type of data structure that contains collections of data.
- The data in an array can be primitive or referenced.
- The parts of an array comprise of elements and indices. An element is a singular value in an array, while an index is the position of a value in the array. Java uses 0-based indexing, meaning the first value of an array is at index 0.
- Method 1 of initializing arrays: int[] array = new int[10]; This declares an array with 10 elements with int type.
- Method 2 of initializing arrays: int[] array = {1, 2, 3, 4}; This specifies the initial values of an array.
- To traverse through an array, any sort of iteration, specifically basic for loops and enhanced for loops, should be used.
- The array.length method returns the length of an array, or in other words the number of values in an array. The array[i] method returns the element of an array at index i.
// Import Java Arrays library
import java.util.Arrays;
public class ArrayMethods {
// Initialized array with private modifiers
private int[] values = {1, 4, 3, 5, 6, 8, 7};
// Swap method for reversing the entire array
public int[] swap() {
int[] valuesSwap = values.clone();
for (int i = 0; i < valuesSwap.length/2; i++) {
// Store the ith value of the array in a temp variable
int temp = valuesSwap[i];
int lastIndex = valuesSwap.length - (i + 1);
valuesSwap[i] = valuesSwap[lastIndex];
valuesSwap[lastIndex] = temp;
}
return valuesSwap;
}
// Replace method for replacing all even numbers in the array with 0
public int[] replace() {
int[] valuesReplace = values.clone();
for (int a = 0; a < valuesReplace.length; a++) {
// If % produces a remainder of 0, the element is even
if (valuesReplace[a] % 2 == 0) {
valuesReplace[a] = 0;
}
}
return valuesReplace;
}
// Running method for visualizing outputs
public static void main(String[] args) {
ArrayMethods myObj = new ArrayMethods();
for (int num : myObj.swap()) {
System.out.print(num + " ");
}
System.out.println("");
for (int num : myObj.replace()) {
System.out.print(num + " ");
}
}
}
ArrayMethods.main(null);