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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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 ...
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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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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
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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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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 ...
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2answers
734 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
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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
774 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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414 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
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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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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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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
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Populating a vector with alternating numbers

This code inserts the number 4 into a vector's even indexes. ...
4
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1answer
788 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
957 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
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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
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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 ...
2
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1answer
297 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
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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
628 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
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`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
383 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
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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
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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
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Using std::vectors to store textures

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

Printing a multilevel container

I have these struct(s) to keep data about temperature measurement: ...
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2answers
449 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
832 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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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
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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
989 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
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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
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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
508 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 ...
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1answer
382 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
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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 ...
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1answer
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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 ...
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2answers
762 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'...
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2answers
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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
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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 ...
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2answers
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Sorted vector (aka flat_set) for objects (pointers) with custom embedded key (functor used)

BEFORE YOU READ: this link should be included when you just don't like the format of the question and for those that read this question for the first time, the link may give you the idea what happened ...
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2answers
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Optimizing a particle filter weighted selection step

I have a vector with 10000 particles that I use in a Particle Filter. The problem is that it's taking too long to compute the weighted selection of the particles. I want to use a vector of weights (<...
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4answers
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STL vector implementation

I've implemented a simple vector-like structure. I would appreciate all criticism relevant to code, style, flow, camelCase vs underscore, and so forth. ...
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3answers
640 views

Determine whether one vector is a prefix of the other

Exercise 5.17: Given two vectors of ints, write a program to determine whether one vector is a prefix of the other. For vectors of unequal length, compare ...
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3answers
370 views

Inner product of random floats written to file

My goals are to make this code: faster more idiomatic C++ What the code does: take an integer command-line argument N make a vector of ...