Questions tagged [custom-compare]
26 questions
10
votes
2 answers
Why can not we use `std::multiset` with custom compare lambda as the value of a `std::map`?
This is a follow-up question of asked
How to provide custom comparator for `std::multiset` without overloading `operator()`, `std::less`, `std::greater`?
and I have tried to solve by the following manner.
Basic
One can provide custom compare lambda…
JeJo
- 30,635
- 6
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- 88
9
votes
2 answers
LinQ distinct with custom comparer leaves duplicates
I've got the following classes:
public class SupplierCategory : IEquatable
{
public string Name { get; set; }
public string Parent { get; set; }
#region IEquatable Members
public bool…
NDM
- 6,731
- 3
- 39
- 52
6
votes
1 answer
how to sort the child nodes of treeView
I want to sort a given TreeView child nodes in alphabetical order.
Suppose my tree View is like this:
firstNode1
secondNode1
thirdNode1
thirdNode2
thirdNode3
...
firstNode2
secondNode1
thirdNode1
thirdNode2
thirdNode3
...
I want to sort the…
theburningfire
- 481
- 1
- 4
- 20
5
votes
3 answers
How to use priority_queue with a non-static compare method of class instance?
Suppose I have a simple class like this:
class Test {
public:
Test(int reference) { m_reference = reference; }
void feed(int x) { m_data.push_back(x); }
int get() { return m_data.front(); }
private:
int m_reference;
std::vector…
Delgan
- 18,571
- 11
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- 141
4
votes
1 answer
How to sort a Hashmap on Key based on Custom Comparator
I am receiving a Hashmap for a common process that I need to sort on the Key using a custom comparator.
Below is what I have tried, but it does not seem to work - it is not sorting the keys.
The keys of the map are of the form long-string-short…
adbdkb
- 1,897
- 6
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4
votes
3 answers
How to provide custom comparator for `std::multiset` without overloading `operator()`, `std::less`, `std::greater`?
I want a custom comparator for the following code. However, I am not allowed to overload operator(), std::less, std::greater.
I tried to achieve this using lambda but gcc won't allow me to use auto as a non-static member. Any other way to make…
Sumit Dhingra
- 123
- 9
3
votes
2 answers
Custom compare function for std::multimap when keys are equal
I would like to code a custom comparator for a std::multimap. What I would like to do is to compare the keys, in case they are equal, then compare the values. I'm trying to do it by overloading the operator() in a struct and passing the function…
Jules
- 134
- 1
- 10
2
votes
2 answers
std::set of MyElement with MyElement::SomeMethod as custom comparator
I have a simple MyElement class, and I would like to use a bool MyElement::SomeMethod(...) {...} as the custom comparator for a std::set of MyElement items.
I have made my research, and I am already aware of some alternative solutions, which I list…
vaeVictis
- 484
- 1
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- 13
2
votes
1 answer
How to sort w.r.t. certain parameter using C++ custom compare function?
I am trying to sort points on a plane by their polar angle w.r.t. the point O. The simplified version of the code looks like this:
bool comparePolar(point A, point B, point O){
//if point B lies to the left of the edge OA, return false
…
Archil Zhvania
- 123
- 7
2
votes
3 answers
How to sort std::set according to the second element?
Given n points in a two-dimensional space, sort all the points in ascending order.
(x1,y1) > (x2,y2) if and only if (x1>x2) or (x1==x2 && y1
user11376749
2
votes
3 answers
Should a custom comparer for strings allow for null values
I'm looking at someone elses code for a custom comparer that compares strings.
I'm noticing that it will fall over if at least one of the string parameters is null.
The compare returns -1, 0 or 1 based on the result of the comparison.
Should code…
Coder 2
- 4,761
- 12
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- 43
1
vote
1 answer
Using same function for sorting a vector and custom comparator in set
This might sound like a stupid problem but I wondered for a long time is there a better way that this:
struct X
{
int a;
int b;
};
bool sortComp(const X first, const X second)
{
if (first.a!=second.a)
return (first.a
NoSenseEtAl
- 28,205
- 28
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1
vote
0 answers
How to use sorted using key=lambda instead of cmp_to_key?
Given an array A of non-negative integers, arrange them such that they form the largest number.
example :
A = [3, 30, 34, 5, 9]
output : "9534330"
I am able to do this using custom compare function, is it possible to achieve the same using…
msmd_shafeeq
- 11
- 1
1
vote
3 answers
Why does this simple custom-comparator of tuples crash even with strict-weak ordering?
This simple custom-comparator for type tuple crashes for the example test below. I checked with the cout statements in the cmp comparator that each call to cmp gets a return value, so it's not like the values in the tuples t1 and t2…
Joe Black
- 625
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- 19
1
vote
2 answers
Writing a proper implementation of compareTo
private static class CharacterIndex implements Comparable {
private final char c;
private final int index;
public CharacterIndex(char c, int index) {
this.c = c;
this.index = index;
}
}
Now I want…
Lavish Kothari
- 2,211
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- 29