An array is a way to store values of the same type. If I need to store scores for 100 students, I could declare 100 variables, but it would be much simpler to declare a single variable with 100 places in it (called "elements"). There are two ways to declare arrays in Java: Do it this way if you know what the elements will be already: double [] temps={99.5,44.7,86.3,100.3}; //alternatively, you can do: //double temps[]={99.5,44.7,86.3,100.3}; Otherwise, do it this way: double [] temps=new double[4]; //where 4 is the number of //elements in the array Note that arrays are indexed from 0 to the number of elements in the array -1. In the first example above: temps: 99.5 44.7 86.3 100.3 [0] [1] [2] [3] We refer to each element by its "index" or "subscript". Example: temps[0]=99.5; Practice: How would you declare an array to store 5 integers? How would you declare an array to store 5 letter grades and assign the array the values 'A' 'B' 'C' 'D' and 'F'? For Loops and Arrays often go together, because you can use the for loop control variable (the counter) to index the array. For example, given: int scores[]={96,85,73}; To print these scores, you could write: System.out.println(scores[0]); System.out.println(scores[1]); System.out.println(scores[2]); Or you could use a loop instead: for (int counter=0;counter<3;counter++) System.out.println(scores[counter]);