equality

问题 How do you compare two instances of structs for equality in standard C? 回答1: C provides no language facilities to do this - you have to do it yourself and compare each structure member by member. 回答2: You may be tempted to use memcmp(&a, &b, sizeof(struct foo)) , but it may not work in all situations. The compiler may add alignment buffer space to a structure, and the values found at memory locations lying in the buffer space are not guaranteed to be any particular value. But, if you use

问题 What is the difference between == and === ? How exactly does the loosely == comparison work? How exactly does the strict === comparison work? What would be some useful examples? 回答1: Difference between == and === The difference between the loosely == equal operator and the strict === identical operator is exactly explained in the manual: Comparison Operators ┌──────────┬───────────┬───────────────────────────────────────────────────────────┐ │ Example │ Name │ Result │ ├──────────┼───────────

问题 To narrow it down: I'm currently using Boost.Unordered. I see two possible solutions: Define my own Equality Predicates and Hash Functions and to utilize templates (maybe is_pointer ) to distinct between pointers and instances; Simply to extend boost::hash by providing hash_value(Type* const& x) as for hashing; and add == operator overload as free function with (Type* const& x, Type* const& y) parameters as for equality checking. I'm not sure whether both variations are actually possible,

问题 How we could find max non-repeatable value in the array with a time ~O(N) I was trying to do it during huge time, but I found only ~O(2N): int solution(int[] A) { List<Integer> arr = new ArrayList<Integer>(); Set<Integer> set = new HashSet<Integer>(); int max = 0; for(int i = 0; i < A.length; i++) { if(!set.add(A[i])) arr.add(A[i]); } for(int i = 0; i < A.length; i++) { if (max < A[i] && !arr.contains(A[i])) max = A[i]; } return max; } Could we do it a little bit faster?! 回答1: int A[] = {5, 5

问题 This question already has answers here : Which equals operator (== vs ===) should be used in JavaScript comparisons? (49 answers) Closed 4 years ago . I wonder if there is the same difference between identity === and equality == operators in angular directives like in pure javascript? For example is ng-if="value === 'foo' better than ng-if="value == 'foo' What I checked is that ng-if="true == 1 passes but ng-if="true === 1 doesn't, so it looks like it works the same way like pure js. On the

问题 I've recently noticed something strange when I used if( ... == true) in JavaScript. The == operator should attempt to convert the given data-types to be the same. But some cases don't appear to do that as we would expect: if ( 42 == true ) // false ( Only 1 is true ) if ( "Hello World" == true ) // false ( false for any string ) Although if I convert them myself doing !! to both 42 and "someString" turn out to be true : if ( !!42 === true ) // Shows that 42 cast to a boolean is true. if ( !!

问题 I have a method returning a List<GradingResult> : public class GradingResult { public float Grade { get; set; } public int Score { get; set; } } That list has values from 6 to 1 in float format: 6, 5.9, 5.8, ... 1.2, 1.1,1 Now in my unit test I have a test GradingResult list with test data: new List<GradingResult> { new GradingResult{ Score = 0,Grade = 6.0f}, new GradingResult{ Score = 1,Grade = 5.8f}, new GradingResult{ Score = 2,Grade = 5.7f}, new GradingResult{ Score = 3,Grade = 5.5f}, new

问题 This post is a Community Wiki . Edit existing answers to improve this post. It is not currently accepting new answers. I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? 回答1: == tests for reference equality (whether they are the same object). .equals() tests for value equality (whether they are

问题 Let's say you have two objects that are identical (meaning they have the same properties and the same values respectively). How do you test for equality? Example $obj1 & $obj2 are identical Here's what I've tried: if($obj1 -eq $obj2) { echo 'true' } else { echo 'false' } # RETURNS "false" if(Compare-Object -ReferenceObject $obj1 -DifferenceObject $obj2) { echo 'true' } else { echo 'false' } # RETURNS "false" Edit This is not identical 回答1: You can compare two PSObject objects for equality of

问题 This post is a Community Wiki . Edit existing answers to improve this post. It is not currently accepting new answers. I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? 回答1: == tests for reference equality (whether they are the same object). .equals() tests for value equality (whether they are