20 Dec 2024

Memory Contiguity of std::Vector ElementsConcerned developers often raise the question of whether elements within a std::vector are guaranteed to...

24 Oct 2024

This article examines the potential safety issues when using push_back to insert elements into a vector. It emphasizes the importance of considering reference validity, especially when pushing elements that reference existing elements in the vector.

03 Aug 2025

It is recommended to use the back() member function to get the last element of std::vector, provided that the vector is not empty; 2. You can access the vec[vec.size()-1] or a safe at() method through the subscript, which throws an exception when it is crossed; 3. You can also use iterator methods, such as *(vec.end()-1) or vec.rbegin()[0]; in summary, the most commonly used and efficient method is to call back(), but you must first check whether the vector is empty to avoid undefined behavior. This method is clear in semantics and good in performance, and is suitable for most scenarios.

09 Dec 2024

How to Efficiently Sort a Vector of Pairs by Pair's Second ElementThis article addresses the question of sorting a vector of pairs based on the...

25 Jul 2025

There are four common methods to obtain the first element of std::vector: 1. Use the front() method to ensure that the vector is not empty, has clear semantics and is recommended for daily use; 2. Use the subscript [0], and it also needs to be judged empty, with the performance comparable to front() but slightly weaker semantics; 3. Use *begin(), which is suitable for generic programming and STL algorithms; 4. Use at(0), without manually null judgment, but low performance, and throw exceptions when crossing the boundary, which is suitable for debugging or exception handling; the best practice is to call empty() first to check whether it is empty, and then use the front() method to obtain the first element to avoid undefined behavior.

11 Dec 2024

Erasing an Element from a std::vector by IndexIn C , when working with a std::vector, there may be instances where removing an element by its...