How to Efficiently Trim Excess Capacity in std::Vectors?
Trimming Excess Capacity from std::Vectors
When dealing with large datasets, it's crucial to manage memory efficiently to avoid performance bottlenecks. In C , the std::vector container is commonly used for storing collections of data. However, when the size of the vector changes significantly, it often leaves behind excess capacity that consumes unnecessary memory.
Shrinking a std::Vector to Fit Its Contents
To release the unused capacity from a vector, the "swap trick" technique can be employed. This involves creating a new vector with the same elements as the original but without the excess capacity.
Implementation:
1 |
|
After this swap operation, the original vector is destroyed, and the new vector takes its place with only as much memory as needed for the current elements. This effectively trims the unused capacity, resulting in a more efficient memory footprint.
Why the Swap Trick Works:
The key behind the swap trick lies in the copy constructor of the vector. When a new vector is constructed from an existing one, it allocates only the necessary memory to hold the elements being copied. By utilizing this behavior, the swap trick effectively creates a new vector with a reduced capacity that fits the current number of elements.
By adopting this technique, you can significantly improve memory management for your std::vectors, especially in scenarios where the data size is highly dynamic.
The above is the detailed content of How to Efficiently Trim Excess Capacity in std::Vectors?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics











C language data structure: The data representation of the tree and graph is a hierarchical data structure consisting of nodes. Each node contains a data element and a pointer to its child nodes. The binary tree is a special type of tree. Each node has at most two child nodes. The data represents structTreeNode{intdata;structTreeNode*left;structTreeNode*right;}; Operation creates a tree traversal tree (predecision, in-order, and later order) search tree insertion node deletes node graph is a collection of data structures, where elements are vertices, and they can be connected together through edges with right or unrighted data representing neighbors.

The truth about file operation problems: file opening failed: insufficient permissions, wrong paths, and file occupied. Data writing failed: the buffer is full, the file is not writable, and the disk space is insufficient. Other FAQs: slow file traversal, incorrect text file encoding, and binary file reading errors.

The history and evolution of C# and C are unique, and the future prospects are also different. 1.C was invented by BjarneStroustrup in 1983 to introduce object-oriented programming into the C language. Its evolution process includes multiple standardizations, such as C 11 introducing auto keywords and lambda expressions, C 20 introducing concepts and coroutines, and will focus on performance and system-level programming in the future. 2.C# was released by Microsoft in 2000. Combining the advantages of C and Java, its evolution focuses on simplicity and productivity. For example, C#2.0 introduced generics and C#5.0 introduced asynchronous programming, which will focus on developers' productivity and cloud computing in the future.

Algorithms are the set of instructions to solve problems, and their execution speed and memory usage vary. In programming, many algorithms are based on data search and sorting. This article will introduce several data retrieval and sorting algorithms. Linear search assumes that there is an array [20,500,10,5,100,1,50] and needs to find the number 50. The linear search algorithm checks each element in the array one by one until the target value is found or the complete array is traversed. The algorithm flowchart is as follows: The pseudo-code for linear search is as follows: Check each element: If the target value is found: Return true Return false C language implementation: #include#includeintmain(void){i

C language multithreading programming guide: Creating threads: Use the pthread_create() function to specify thread ID, properties, and thread functions. Thread synchronization: Prevent data competition through mutexes, semaphores, and conditional variables. Practical case: Use multi-threading to calculate the Fibonacci number, assign tasks to multiple threads and synchronize the results. Troubleshooting: Solve problems such as program crashes, thread stop responses, and performance bottlenecks.

How to output a countdown in C? Answer: Use loop statements. Steps: 1. Define the variable n and store the countdown number to output; 2. Use the while loop to continuously print n until n is less than 1; 3. In the loop body, print out the value of n; 4. At the end of the loop, subtract n by 1 to output the next smaller reciprocal.

C language functions include definitions, calls and declarations. Function definition specifies function name, parameters and return type, function body implements functions; function calls execute functions and provide parameters; function declarations inform the compiler of function type. Value pass is used for parameter pass, pay attention to the return type, maintain a consistent code style, and handle errors in functions. Mastering this knowledge can help write elegant, robust C code.

Integers are the most basic data type in programming and can be regarded as the cornerstone of programming. The job of a programmer is to give these numbers meanings. No matter how complex the software is, it ultimately comes down to integer operations, because the processor only understands integers. To represent negative numbers, we introduced two's complement; to represent decimal numbers, we created scientific notation, so there are floating-point numbers. But in the final analysis, everything is still inseparable from 0 and 1. A brief history of integers In C, int is almost the default type. Although the compiler may issue a warning, in many cases you can still write code like this: main(void){return0;} From a technical point of view, this is equivalent to the following code: intmain(void){return0;}
