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\$\begingroup\$ Creating byte data[length]; then creating a vector forces a copy. Why not make data a vector and simply return it. Then the compiler can do lots of optimization and build the vector directly at the destination so removing the need for a copy. \$\endgroup\$ –
I profiled a library I'm writing that uses vector transposes and found that I am spending a good bit of time doing the following transpose. I am using a std::vector of std::vector<double>s to
10. I am preparing for an interview and came to know about this question: implement a vector class in C++. I thought of how I would write it an interview and included the code below. The things I know I did not cover already are: 1) No use of templates for different data types 2) No use of iterators for iterating.
I have ended up with the following code in order to filter out some bad elements from a std::vector: #include <iostream> #include <vector> #include <algorithm> typedef struct my...
The only difficulty is ensuring this isn't used after the owning vector goes out of scope. The simplest implementation is something like: std::vector<char*> strlist(std::vector<std::string> &input) {. std::vector<char*> result; // remember the nullptr terminator. result.reserve(input.size()+1);
I am learning about templates in C++ so I decided to implement an N-dimensional vector. The code seems to work fine, but there are a few things that I am unsure about. To stop GetW() being called on a 3-dimensional vector, I used std::enable_if .
The first version of the algorithm uses a traditional C++03-era for loop with iterators. The only modern element is the auto used to deduce an std::vector<std::string>::iterator. The second loop uses a C++11 range-based for loop whose syntax is close to the one used in Java.
11. I'm extremely new to C++ and am doing the exercises on the book Accelerated C++. Here is one of the exercises: 4-5. Write a function that reads words from an input stream and stores them in a vector. Use that function both to write programs that count the number of words in the input, and to count how many times each word occurred.
The implementation of an iterator is based on the "Iterator Concept". There are actually five types of iterator in C++. But since you are using vector as your example implementation we should consider the "Random Access Iterator Concept". To qualify as a random access iterator you have to uphold a specific contract.
If the data can be sorted and de-duplicated, then the most efficient way to find an entry is to store the data in a std::set. Storing the data takes a little longer (O (log n) for the set vs. amortized O (1) for the vector), but finding the data makes up for it (O (log n) for the set vs. O (n) for the vector).