I’ve been learning Java for a while and I’ve run into a problem I can’t figure out. I am currently learning arrays and how to iterate through them using loops. I generally understand how the if statement and the for loop work, but in this case I don’t understand the principle of this l…
Tag: iteration
Planets won’t render when using for-loop in libgdx
I am running an N-body simulation (testing with three planets at first) and it appears when I use a for-loop to do so, all of the planets don’t render and while debugging i found out they don’t even have an address. However, if I manually type in the movement of all three planets it works. Here…
No ConcurrentModificationException during index based iteration
I have following code: I expected it to throw ConcurrentModificationException but it is working fine. Can some explain the reason? Answer The reason is you are not technically iterating the List. Instead you are random accessing the list using a incrementing index, and removing some values. If you change to c…
Problem with exercise where i have to iterable through MyObject
I have exercise: define an Incrementer class to get the code from main class gave the result: gave the result: Requirement: the program (including the Incrementer class) cannot use tables or collections. Hints: in (…) and by (…) are methods in the Incrementer class Incrementer should implement the…
Finding the longest run of duplicate numbers in an ArrayList? (Beginner java)
This is my first time using stack overflow, so I’m so sorry if this is formatted incorrectly in any way. For a comp sci project, I have to do some different things to a 40-item Array List of random numbers. The task I’m struggling with is this: Count the longest run of the same number. A run conti…
Ignoring blank lines in CSV file in Java
I am trying to iterate through a CSV file in Java. It iterates through the entire file, but will get to the end of the file and try to read the next blank line and throw an error. My code is below. Like I typed, this works fine until it gets to the end of the file. When it gets
Doing a beginner’s course on Java, having problems with do-while and if-else loops, as well as string validation
I’m doing a beginners course on Java, and there is no one currently I can ask for help. The program is simple, you put in your details and the program will offer you a price quote for car insurance. The program is supposed to give quotes to those between the ages of 18 – 70. Out with that the prog…
Iterate an Enumeration in Java 8
Is it possible to iterate an Enumeration by using Lambda Expression? What will be the Lambda representation of the following code snippet: I didn’t find any stream within it. Answer In case you don’t like the fact that Collections.list(Enumeration) copies the entire contents into a (temporary) list befo…
Fastest way to iterate over all the chars in a String
In Java, what would the fastest way to iterate over all the chars in a String, this: Or this: EDIT : What I’d like to know is if the cost of repeatedly calling the charAt method during a long iteration ends up being either less than or greater than the cost of performing a single call to toCharArray at …
Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop
We all know you can’t do the following because of ConcurrentModificationException: But this apparently works sometimes, but not always. Here’s some specific code: This, of course, results in: Even though multiple threads aren’t doing it. Anyway. What’s the best solution to this problem…