problem about comparator-Collection of common programming errors
kellax
java compare comparator
It has been asked before, but I have not found a decent implementation with an explanation.public int compareTo(Object o) {if (this == null || o == null){ return 0;}Tok tmp = (Tok) o; if (this.rang < tmp.rang){return -1;} else if (this.rang > tmp.rang ) {return 1;} else {return 0;} }I read two similar questions that I found yet; they insist on implementing another method. I do not understand why this should not work. The method gets an extra object and it checks if its a valid instanc
Abubakkar Rangara
java comparator comparable
when implementing the comparator interface to achieve natural ordering of objects : say if we had the class Account:class Account {Account(String name, int id) int balance() void deposit(int n) }we wanted to sort the Account balances of two accounts in orderwhats the diffrence between these two methods?public class comparebalances implements Comparable <Account> {public int compare (Account acc1, Account acc2){return acc1.balance()-acc2.balance();}}public class comparebalances implements C
Nick Holt
java random comparator
I’m a student teaching myself about Comparators and I came across odd behavior that I’m having trouble understanding. I’m attempting to shuffle an array using Arrays.sort and a Random object, however when I seed the Random object the shuffle either reverses the array or does nothing. Not seeding the Random object leads to it being shuffled as expected.No seed:Integer[] integers = new Integer[]{1, 2, 3, 4, 5, 6}; Arrays.sort(integers, new Comparator<T>() {@Overridepublic int compare(T o1, T
arnuschky
op-amp voltage-divider comparator
I have a dual op-amp that I want to use as a comparator: Vin should be compared to Vref (1/2 VCC). This is the circuit that I am using (as I have a dual op-amp, I am using a voltage follower on the divider).I would expect that if Vin>1.65V, Vout=3.3V (VCC). Otherwise, Vout=0V. Unfortunately, Vout is around 2.2V if Vin>1.65V, which is not sufficient for my µC to detect a clean logic high. I suspect that I am experiencing an “ideal vs. real-world” op-amp problem, but I am not sure how to resolve i
Joachim Sauer
java sorting comparator
What will happen if I supply a non-transitive Comparator to Collections.sort? Can I run into infinite loop?A small test I wrote produced an output, but I want to make sure this will always be the case.The problem is that in some cases, my comparator can produce cycles, and in this case I just want to make sure it will not run into infinite loop. I don’t care about the actual result.
Westerley
sensor op-amp current comparator
I need to detect if a load resistor is taken out of circuit. The load resistor is a photoresistor and can vary from 50k\$\Omega\$ up to 2M\$\Omega\$ and is driven by +5V to ground. The approach I thought of was to put a small sense resistor between +5V and the load, and use a comparator to detect the voltage drop across the sense resistor. When current is flowing, there will be a drop across the sense resistor, one comparator input will be higher than the other and so the comparator output will
Oli Glaser
led digital-logic switches comparator
This is a dead easy question for most of you! But I’m relatively new to circuit design, so I’d just like to ask whether this circuit might work (at all!)Here’s a picture of the circuit Basically, what it’s trying to do is if the push to make switch is NOT triggered, then it should sound the buzzer, and light the LED. When the push to make switch IS triggered, then it does nothing. The toggle switch on top triggers whether the circuit is running or not, as checked by the AND gate. It’s meant to b
Chii
java comparator treemap
public final Comparator<String> ID_IGN_CASE_COMP = new Comparator<String>() {public int compare(String s1, String s2) {return s1.compareToIgnoreCase(s2);}};private Map< String, Animal > _animals = new TreeMap< String, Animal >(ID_IGN_CASE_COMP);My problem is, how to use method get(id) ignoring the given comparator. I want the map to be order by Case Insensitive but, I want it to be case sensitive when I fetch the values by a given key.
Miguel Rodrigues
java collections arraylist comparator treeset
I need to sort a java collection of objects by an Integer value “level”. I also need to determine if this collection already contains an object by “title”. I believe the best choice of a collection is a TreeSet to have an ordered set of unique values.I have an object with the “level” and “title attributes. It implements comparable like so:It overrides the Equals method (for checking if the object is already contained in the TreeSet by “title”. The code looks like:@Override public boolean equ
Robo
c++ duplicates comparator
I am trying to remove duplicate items from vector using the following comparatorbool operator() ( const Point * p1, const Point * p2 ) const{return ( p1->X() < p2->X() ) || ( ( p1->X() == p2->X() ) && ( p1->Y() < p2-Y() ) );}and overloaded opeartor ==bool Point::operator == ( const Point &p ) const {return ( x – p.x ) * ( x – p.x ) + ( y – p.y ) * ( y – p.y ) < DIFF; }schematic removing:std::sort ( it_begin, it_end, Comp ); Points::iterator i_new_end = std::un
Kejia
java sorting concurrency comparator
I am using java.util.concurrent.ConcurrentSkipListSet. I define a class People whose objects are held in a ConcurrentSkipListSet<People>, a Comparator<People> comparing Age of People, and that ConcurrentSkipListSet<People> object is constructed via this Comparator<People>. If I have two People objects having the same Age, e.g. a.Age.equals(b.Age), what happens? Both a and b in the ConcurrentSkipListSet? Or only one?It’s required that such a Comparator must be consistent w
YourBestBet
generics constructor comparator treemap
The value type of my map is a List<Pair<Integer, String>>I want to sort it by the left side of first pair in the list. But there is an error said:The constructor TreeMap<String,List<Pair<Integer,String>>> (Comparator<List<Pair<Integer,String>>>) is undefinedHere is my code:import java.util.TreeMap; import org.apache.commons.lang3.tuple.Pair;Map<String, List<Pair<Integer, String>>> data = new HashMap<String, List<Pair<Int
FernandoSBS
javascript operators comparator
How to right this syntax correctly:if (tipoTropaPrioritaria[m] || troopsCount[m] || availableTroops[m]) == (“null” || “undefined”) {…}(to check if any of the first 3 variables is null or undefined)
BSEE
adc measurement comparator
Here is revision 6 of the circuit. Hows it look? :)(This is an ohmmeter circuit. It measures resistances from 1 to 10M ohm with an accuracy of 1%. The resistor (not shown) is measured between J5 and J6. The comparator goes to the wakeup pin of a uC. The uC then wakes up and takes a reading using the SPI interface on the ADC. )
Domi
java generics comparator
I’ve been looking around to see if I find something to help me with my problem, but no luck until now. I’ve got the following classese:public interface ISort<T> {public List<T> sort(List<T> initialList);}public abstract class Sort<T> implements ISort<T> {private Comparator<? super T> comparator;public Sort(Comparator<? super T> comparator) {this.comparator = comparator;}@Overridepublic List<T> sort(List<T> initialList) {ArrayList<T> lis
Dan
java sorting comparator
I learned how to use the comparable but I’m having difficulty with the Comparator. I am having a error in my code: Exception in thread “main” java.lang.ClassCastException: New.People cannot be cast to java.lang.Comparableat java.util.Arrays.mergeSort(Unknown Source)at java.util.Arrays.sort(Unknown Source)at java.util.Collections.sort(Unknown Source)at New.TestPeople.main(TestPeople.java:18)Here is my code:import java.util.Comparator;public class People implements Comparator{private int id;privat
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