Arrays
Array Notes & HW
Arrays
Data Type (reference data type) refers to an object Primitives vs Reference: lower vs UPPER
arrays and ArrayLists
Array Syntax
int[] array = new int[10]; int[] array = (10, 2, 3, 4, 5);
Traverse Array
You can use any sort of loop, main method is through for loops which is easiest way to access array indices.
College Board
Min max and sum of arrays Array.length() to find how long arrays are and access at specific index array[]
HW
Options for hacks (Pick two):
- Swap the first and last element in the array
- Replace all even elements with 0
// Write array methods for the Array Methods class below out of the options given above.
public class ArrayMethods {
private int[] values = {1, 2, 3, 4, 5, 6, 7, 8};
public void printElements(){
for(int i = 0; i < values.length; i++){
System.out.println(values[i]);
}
}
public void swapElements(){
int lastElement = values[values.length-1];
values[values.length-1] = values[0];
values[0] = lastElement;
}
public void replaceAllZero(){
for(int i = 0; i < values.length; i++){
values[i] = 0;
}
}
public static void main(String[] args){
System.out.println("First and Last Element Swap: ");
ArrayMethods swapElements = new ArrayMethods();
swapElements.swapElements();
swapElements.printElements();
System.out.println("Replacing All Elements w/ Zero: ");
ArrayMethods replaceAllZero = new ArrayMethods();
swapElements.replaceAllZero();
swapElements.printElements();
}
}
ArrayMethods.main(null);