int[] numbers = new int[5]; .. System.out.println(numbers[0]); That would print 0 as well. An array of integers without setting a value will have 0 by default. If you receive x = 480, y = 360, num2 = 2 (we don’t know num1), lets assume num1=1 X[num1-1] = x; Y[num1-1] = y; this would be X[1-1] … Read more
private prevents a variable from being accessed directly by another class. You cannot write d.x to read or write to x. If the class chooses to return a reference to x via a public method, though, that’s it’s own choice to pierce the veil of privacy. Nothing stops A from allowing x to be read … Read more
nmb++ is equal to nmb = nmb + 1. It only adds one till it’s 101, which is when it stops. You should add a new variable, let’s call it total, and sum nmb to it every iteration. public class T35{ public static void main(String[] args) { int nmb; int total = 0; for(nmb= 1; … Read more
If you want to create a function which adds 1 to its input, the method to create that function doesn’t need an parameters… but then you need to call that function in order to execute it. I suspect you wanted: import java.util.function.Function; public class LambdaExpression { public static Function<Integer, Integer> create() { Function<Integer, Integer> f … Read more
You simply did not initialize the array correctly: String[] options = ( “Delete Task”, “Return” ); Replace the () by {} to get: String[] options = { “Delete Task”, “Return” }; You can further refer to Array Initializers to get more info on how to initialize an array. (Also next time, please indicate the line … Read more
A NullPointerException, most of the time, means that you’re dereferencing a null variable. I assume the line causing the exception (line 97 in z.java, as the stack trace indicates) is the following line: yy.getXs().add(s); Then it can mean two things: yy is null The list returned by yy.getXs() is null. Use a debugger to identify … Read more
ArrayLists will have an ever so slightly higher overhead than an array. This is because an ArrayList is just a wrapper for an array with a few convenience methods added. Though if you know exactly how many elements you will ever have then ArrayList doesn’t add much. The biggest advantage of having an array over … Read more
The reason is name and id are null. When you retrieve this.id, it returns the value of this classes (ProductEntry) member variable rather than its super class (which is what you want in this case). If these member variables weren’t defined in ProductEntry, a call to this.id would retrieve the id from the super class, … Read more
A MySQL query command with this WHERE clause will find the records you want. WHERE lastdatechangeoil <= NOW() – INTERVAL 3 MONTH as long as that information is stored in a DATETIME or TIMESTAMP column. solved Getting all entries in a particular number of months [closed]
You don’t store the input numbers, if you only want to print them in the end it is sufficient to store them in a string numbers += ” ” + Integer.toString(number);. The whole main would then look something like that: public static void main(String[] args) { int mstop; int number; int sum; int mcounter; String … Read more
Please have a look at the org.jfree.demo.TimeSeriesChartDemo1 class that is included in the JFreeChart download. The source code is included in the source download of JFreeChart, so it’s a good point to start with. I think that’s what you want. Update (revised on your comment): You can change the format of axis labels by redefining … Read more
In Java, the test if (i==f && i.equals(f)) is nonsensical. Since i is an Integer and f is a Float, they will never be == (and, since they are incommensurate types, cannot legally be compared with ==). For reference types, the == operator evaluates to true only if the variables reference the same object, which … Read more
I strongly recommend you watch freeCodeCamp – Graph Theory video, as a Computer Science student that video had a lot of information that were hard to get/understand in my college course, even though BFS and DFS aren’t that hard yet still important to know them along with other Graph Algorithms solved What are the foundations … Read more
Here it’s: public String size(int size){ String hrSize = “”; double m = size/1024.0; DecimalFormat dec = new DecimalFormat(“0.00″); if (m > 1) { hrSize = dec.format(m).concat(” MB”); } else { hrSize = dec.format(size).concat(” KB”); } return hrSize; } SOURCE: Converting KB to MB, GB, TB dynamically 1 solved How to get file size in … Read more
You should make the constructor of class User as public. 0 solved Java / my classes are not seeing each other?