Questions tagged [vectors]

Vectors are sequence containers representing arrays that can change in size. For questions about geometric or algebraic vectors, use [coordinate-system] instead.

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178 views

An Alternative Vector (Copy Assignment Operator)

This is a continuation of An Alternative Vector, taking a closer look at the copy assignment operator. In the following code, I am only posting the new version of the copy assignment operator; all ...
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4answers
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An alternative vector

Based on this question (as a starting point) and a couple of other questions about rewriting vector in C++, I am planning to write another blog article to show the best way (or more precisely, the ...
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2answers
346 views

Simple class for 2D <-> 1D array index conversion

I made a class to convert the index between 2D and 1D arrays. For example, between {1,3,5,7,9,11} and {{1,3},{5,7},{9,11}} When i is 0, ...
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1answer
104 views

Redirecting arriving customers to the nearest empty queue

I have a task to make a checkout line controller. First it receives, as input, an amount of checkouts and commands. Then commands that are C for coming and L for leaving, and after those the number of ...
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3answers
183 views

Performing operations on a processed int vector

This question came from C++ Primer 5th edition: Q: Read a set of integers into a vector. Print the sum of each pair of adjacent elements. Change your program so that it prints the sum of the ...
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1answer
1k views

Process string vector and change each string to uppercase

The question below came from C++ primer 5th edition. Read a sequence of words from cin and store the values a vector. After you’ve read all the words, process ...
2
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1answer
2k views

Matrix column switching

I'm currently working in the math library for a game framework that I'm writing and am working to improve some functionality that was affected during a refactor. Formerly, my ...
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2answers
5k views

Vector Sort Function

I had heard about sorting for a while, but never actually gave it a try. So I decided to make an algorithm that would sort the members of a vector from least to greatest. Though this may seem pretty ...
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1answer
1k views

Comparing std::vector<bool> to std::vector<char>

A recent comment to an answer of mine here on Code Review brought up an interesting point. The comment was that one should use std::vector<char> over ...
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2answers
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Vector Implementation C++

I have attempted to implement a similar version of the STL Vector; several functions are missing but I'd like a few words of advice on whether I am indeed on the right track or whether I should change ...
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2answers
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Counting inversions in C++ via mergesort and vectors [closed]

I have a text file that contains 100,000 numbers from 1 ~ 100,000 in an unsorted manner (no duplicates). The name of the file is "IntegerArray.txt" My task is to count the number of inversions in ...
5
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2answers
778 views

Multiplayer BlackJack using Vector

This is a small program I wrote for GCSE computing, it operates using Vectors and that's pretty much it, wondering if you could tell me if there is anything I could do better. BlackJackv2.cpp ...
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4answers
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Custom vector that uses less memory than std::vector

I'm using vectors to create matrix and the vector itself is consuming a large space. So I implemented a version that would use less memory and, if possible, be as fast or faster than ...
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2answers
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Mean, Median and Mode of a QVector

I would like some help condensing this code down to size. I am trying to utilize Qt's container classes as efficiently as possible. I do not believe this code reflects my objective. ...
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2answers
104 views

Convert hex encoded string to byte array

The following should read a hex string such as "ece998a2fb" into vector 236 233 152 162 251. I was unable to find any built in ...
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1answer
785 views

Divide and Conquer algorithm for counting inversions

I've written a program that counts the number of inversions using a Divide and Conquer algorithm, written in C++11. ...
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2answers
438 views

Implementation of Vector in C++

This is a simple implementation of vector in C++. Please offer your reviews to improve the code. ...
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2answers
1k views

Creating n-dimensional mathematical vector classes through inheritance

Right now I have no knowledge of templates, but I just finished learning about inheritance, and wanted to apply it to a Vector3 class that I had already created. My ...
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0answers
449 views

Flattening lists of Vectors and Matrices into arrays

For many optimisation methods the parameters must be given as a single vector, such as Optim.jl. But for many interesting functions the parameters/coeffients to be optimised are matrices, or a mixture ...
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0answers
33 views

Constant-space n-dimensional loops using dependent vectors

I designed this file after learning from this awesome answer from user2407038 on Stack Overflow. The idea of the module is to replace code like: ...
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3answers
157 views

Populating a vector with alternating numbers

This code inserts the number 4 into a vector's even indexes. ...
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1answer
882 views

Generic vector implementation in C using macros

I while ago I experimented with macros in C and came up with the idea of implementing a generic vector library using macros. This code uses the non standard typeof ...
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3answers
1k views

Writing huge 2D vectors to text file too slow

I have 10 large (34 million cell) 2D gridded vectors storing doubles. When written they are over 200 MB in size. I use an ofstream object to write them to a text ...
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2answers
554 views

How to speak Brainfuck: for beginners

The following code transforms multi-line input into the the Brainfuck equivalent. One line turns into one program. The resulting programs are split by newlines for readability. Brainf.cpp ...
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1answer
1k views

Passing functors to standard algorithms

I created 3 different implementations (which produce the same results) using the count_if function from STL. I wish to check the number of elements in the vector ...
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1answer
301 views

Second implementation of std::vector

Having already attempted an implementation of the std::vector class here, I decided to take the comments on board and also do some new bits myself (mainly the ...
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2answers
139 views

Fastest way to search istringstream for patterns in around 0.02 seconds

Problem I have a stream composed of 2 columns and 1000 lines: Column 1: contains the patterns that I want to find Column 2: contains the values corresponding the the patterns in Column1 I want to ...
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1answer
655 views

Implementation of std::vector class

I decided to implement the std::vector class in C++, and was wondering if I had done everything correctly. When I mean 'correctly', I mean that the code is ...
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3answers
899 views

`std::vector` 'substring concatenator'

The point of this is to concatenate a vector of std::strings into one string starting at an index of the vector. ...
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0answers
421 views

Serialize/deserialize a vector using insertion/extraction operators

I've never serialized a structure to a file before in C++, so I'm looking for critique on my first try at it. My main concerns are: It uses the streams space-delimited behavior. If a ...
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1answer
213 views

Self Implemented Hash Map Performance

I have written two hash map implementations, one that stores Vertices and one that stores self implemented vectors of Edges. They are all fully functioning, however in my application they are quite ...
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1answer
8k views

Calculating the determinant of a matrix

I wanted to do some exercise and came up with the idea of a good challenge (for my level of course). I tried to implement Laplace's algorithm for computing the determinant, recursively. ...
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1answer
1k views

Maximum sum subarray efficiency — divide and conquer w/ vectors

I have successfully implemented a divide and conquer approach for find the maximum sum subarray (see code below). The code works fine and is correct, however I have an efficiency problem in that in ...
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2answers
1k views

Using std::vectors to store textures

I need to write a TextureManager class which stores Texture objects; the problem is I'm using an ...
2
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1answer
118 views

Printing a multilevel container

I have these struct(s) to keep data about temperature measurement: ...
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2answers
455 views

Array of pointers data structure

Does this data structure make sense? It's essentially a vector of pointers, intended to point to larger objects. In effect, it gives the benefit of a linked list, with an \$O(1)\$ lookup at the cost ...
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1answer
857 views

Selecting variable amount of vector elements in C++

Suppose we are given a C++ vector. We want to specify a variable amount of indices and select elements from a vector being indexed. I have two implementation: (A) one relies on C++11 initializer lists,...
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0answers
257 views

C++ vector implementation errors

I haven't really programmed in C++ for about a year, and realised that I should get back into it, and tried my abilities out by remaking the STD vector class. However, my C++ is a bit rusty at the ...
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2answers
8k views

Defining std::vector::push_back(new Object)

Is this the best way to construct a vector of 2D points for return? I don't entirely understand new and delete so I'm concerned ...
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1answer
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Managing initialization for a vector abstract data type in C

As an assignment, I was to create an \$n\$-dimensional vector type for \$n \le 20\$. This vector only has to support addition and scalar multiplication. I tried to write good code, with proper memory ...
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1answer
1k views

Vector implementation

This is a C++ Vector that I've made for the pleasure of it. It was made on a whim and is not related any school assignment or anything alike this. This Vector does ...
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2answers
6k views

Longest string in a vector — two implementations

I was given this piece of code, which calculates the length of the longest string in a vector of ...
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2answers
1k views

Wrapper function to do polynomial fits with gsl

I have two arrays of double, say x and y containing some physical data. I would like to find ...
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2answers
516 views

Basic myVector class raw vs smart pointer

I'm writing a myVector class for a class I'm taking. I don't believe I'm "strong" with smart pointers right now, so that's my question. This is just an excerpt ...
5
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1answer
386 views

Random interval generator for a game

I have been working on a few games which all have a need to create "events" randomly over time. The intervals need to get shorter as time goes on if the event is negative or they need to get longer ...
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2answers
303 views

Vector backed by memory pages

The purpose of this class is to wrap a std::vector in a class so that never a new object is added. We don't allocate a new object on the stack but we trying to fit ...
4
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1answer
2k views

Filling a container with objects using pointers / iterators

I have a series of nested objects that I need to serialize into a byte (unsigned char) array to send out to another computer over UDP. Right now I each object ...
2
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2answers
790 views

Speeding up and shortening a loop [closed]

I'm still relatively new to C++ and I've written a program that could do with being a bit shorter and faster. I use this same set of for loops many times to cycle through the whole tree of values. I'...
4
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2answers
5k views

Read binary file by blocks

I wrote a function that allow me to read a binary file using 3 blocks what ever the length of file. I've decided to divide the length of my file into 3: block 1: ______________ block 2: ...
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2answers
156 views

LinkedVector : a vector of elements with links to other elements

I wanted to have a vector with usual values and with some sort of indexing : an element can have links to other elements (via indices). Something like the following, where ...