In the first case, Derived is a class which can be used to declare a variable. In the second Derived is a variable name of type std::vector<Base>. In the case of the class it is possible to produce undefined behaviour with the following code: void deleter(std::vector<Base>* ptr) { delete ptr; } void buggy() { auto … Read more
Using seq function, you need to following two steps: Step-1 Generate sequence from 2 to 10 using following code: a<-seq(from=2,to = 10) Step-2 Generate sequence from 10 to 2 using following code: b<-seq(from=9,to = 2) Now, combine above two results using following code: data<-c(a,b) The output should as follow: > data [1] 2 3 4 … Read more
Vectors in functions, how to create find and erase function for deleting indexes based on user input (string)? [duplicate] solved Vectors in functions, how to create find and erase function for deleting indexes based on user input (string)? [duplicate]
Your problem is a very specific one. I don’t see how this will be of any use to anybody but yourself. There is no ‘one line solution’. There are many ways to approach indexing problems, I like to use scalar indexing when possible: Ncolumns = size(Matrix,1); Nblocks = floor(Ncolumns/4); %number of 4-line blocks (excluding the … Read more
tight_contour is a std::vector object containing elements of type std::vector<cv::Point>. The (1) is constructing tight_contour to hold 1 initial default-constructed element. 0 solved What does (1) mean when declaring a vector?
the send function doesn’t except uint8_t* so you should cast the contents of the vector like this : (const char*)data1.data(); Also the vector class doesn’t have length () method you should use size() solved C++ sending a vector across a socket connection
If you can’t use std::map, you can associate the word with the frequency: struct Info { std::string word; int frequency; }; //… std::vector<Info> database; //… std::string word; while (std::cin >> word) { // Find the word: const size_t length = database.size(); for (unsigned int i = 0; i < length; ++i) { if (database[i].word == … Read more
After std::vector<float> some_vec; your vector is empty. You must not access any element in it then, because there isn’t any. If you want to put values into it, you need to append them to the vector using push_back() for (some iterator loop here) { //snip some_vec.push_back(some_float); i++; } Alternatively, if you know the size in … Read more
First, you will need to push your prime numbers in the vector. At the beginning, unless you ask otherwise, the vector is empty. You can push a prime number using this snippet: // somewhere you declare your vector std::vector<unsigned long long> primes; // code computing a prime number unsigned long long prime; …. // Push … Read more
Your vector has zero length at start vector<int> binV; //zero length In this line of code for (int i = 0; i < binV.size(); i++){//some code} Will not run because binV is empty This expression is not correct if (input == 1 && input == 0) //not valid This && is logical and operator, if … Read more
vector is template container defined in the STL header <vector> and a part of namespace std . Simply put, it acts like an array whose size can be changed just by adding a new element to it. Just like you store objects of some datatype in an array (for eg. int, char, or any other … Read more
As panta-rei correctly pointed out, it looks like you’re trying to contain a string of the form “string” + string form of (i) but you’re actually doing pointer arithmetic which is illogical in this case (you’re just passing a pointer incremented i from some location – who knows what’s in that memory?). In order to … Read more
The most simple approach would be to just check for every element in src vector, if an duplicate exists in dest vector or not. If it exists just append Duplicate to it, else you can just push back the element as a new element in dest vector. The follow code would do the job – … Read more
You can store non-copyable, non-movable objects in an unordered_set. Finding whether a given element is in the set is O(1) instead of O(n), or O(log n) if you keep the vector sorted (which is itself O(n) on insertion). unordered_set disallows duplicates. Removing a given element is O(1). In the case of a sorted vector, it’s … Read more
A pair of lines associated with two number can only cross if those numbers appear in opposite orders in a and b. Since you state that the first list – a – is sorted (in increasing order) we will only have lines crossing if we pick numbers that are in de-creasing order in b. You … Read more