For vector usage, the additional time consumed by copying data to prevent reallocate memory.
The following two combinations can be used to prevent reallocate.
1. Vector: resize () using array index
2. Vector: Reserve () Use push_back ().
So I tested these two cases on the Windows 2003 platform, and compared them with 3 in which push_back () is directly
Today we want to use vector to realize the function of two-dimensional array, and try to put the two-dimensional vector. Who knows when he got started, he met Ray.
The form of the code is roughly as follows:
VECTOR
The vacuuming operation was performed because the two-dimensional vector was reused. However, th
In practice, the vector series in c ++ -- copy set to vector (do not confuse reserve and resize)
The stl algorithm has a copy function. We can easily write this Code:
#include
#include #include
using namespace std;int _tmain(int argc, _TCHAR* argv[]){ double darray[10]={1.0,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9}; vector
vdouble(10);
Vg.net topology diagram software is a. NET platform based vector Diagram development tool, can be widely used in including: electric power, military, coal, chemical, scientific research, energy and other monitoring software, workflow Designer, power, chemical, coal, industrial control configuration software, simulation, geographic information system, workflow, complex report Industrial SCADA System, ERP process design system, graphic management, graph
650) this.width=650; "src=" Http://twaver.com.cn/Uploads/Product/vgnet/picture_designer_vs2005.png "style=" border : 0px;width:500px;height:400px; "/>650) this.width=650; "src=" Http://twaver.com.cn/Uploads/Product/vgnet/mixing_process_tank_reused.png "style=" border:0px;width:500px;height:400px; "/>Vg.net topology diagram software is a. NET platform based vector Diagram development tool, can be widely used in including: electric power, military, coal
Vg.net topology diagram software is a. NET platform based vector Diagram development tool, can be widely used in including: electric power, military, coal, chemical, scientific research, energy and other monitoring software, workflow Designer, power, chemical, coal, industrial control configuration software, simulation, geographic information system, workflow, complex report Industrial SCADA System, ERP process design system, graphic management, graph
In the Gaussian mixture model, I mentioned the general process of feature processing:
In fact, the Gaussian mixture model completes the task of K-means, then through the Gaussian mixture model clustering, also uses the general distance based method to carry On feature encoding. No, the Gaussian mixture model is usually used in conjunction with Fisher Vector. Now let's make a brief introduction to Fisher Vector
more and more widely valued.
Statistical Learning Theory is based on a solid set of theories and provides a unified framework for solving the problem of Finite Sample learning. It can include many existing methods and is expected to help solve many difficult problems (such as Neural Network Structure Selection and Local Minimization). At the same time, based on this theory, a new general learning method-Support Vector Machine (SVM) has been developed
In practice, the vector series in c ++ -- the second worst iterator failed (deleting elements in the vector)
Directly refer to the Code:
# Include
# Include
Using namespace std; int main () {vector
V; v. push_back (1); v. push_back (2); v. push_back (3); std: vector
: Itera
Previous blogs have talked about some of the ways to use Std::find and std::find_ if. But there is no telling of the classes stored in vectors that are defined by themselves. So how do you use Std::find and std::find_if to find it?First define a class:classitem{Private:STD::stringM_itemid;intM_price;intM_count; Public: Item (STD::stringIdintPriceintcount): M_itemid (ID), M_count (count), M_price (price) {}intGetCount ()Const{returnM_count; }STD::stringGetitemid ()Const{returnM_itemid; }intGetPri
The actual deletion element in the C + + vector uses the std::vector::erase () method in the container Vecrot.Std::remove () in C + + does not delete the element because the container's size () does not change, only the replacement of the element.1.std::vector::erase ()Function prototype: Iterator erase (iterator position); Delete the specified elementIterator Er
JDK source code-Vector, jdk-vector1, Vector:-1, an array of objects that can grow. Similar to an object array, it contains an integer index for component access. However, the Vector size can be increased or reduced as needed.-2. Each Vector optimizes storage management by maintaining capacity and capacityIncrement. Cap
Vector applications (element traversal, insertion, deletion, switching, etc.), vectorHere is a summary of some common applications of vector containers. For the vector constructor and initialization, refer to http://blog.csdn.net/lsh_2013/article/details/21191289. Element Traversal
Use an iterator to access a vector El
Label: gradient descent method, cut vector, method Vector Zookeeper First, it indicates that the gradient is perpendicular to the cut vector of the curve, that is, the gradient direction is the direction of the normal vector: Set the curve x = x (t), Y = Y (T), and z = z (T) to the surface u (x, y, z) = a curve on C (
I write a simple program to distinguish between the vector container size () and the capacity () function, where the capacity function is to reserve space for the vector container, without having to reallocate the memory every time the element is added, thus improving the efficiency a lot. I through a small program to study, the following is the program and running results, more concise can be seen capacity
JQuery generates the svg vector QR code and jquerysvg Vector
JQuery generates a vector svg QR code and provides PNG and SVG page downloads to relieve pressure on the server.
The Code is as follows:
The above section describes how to use jQuery to generate an svg vector QR code. I hope it will be helpful to you. If you
C ++ is based on the vector graphics library cairo graphics, vector graphics cairo
// Sudo apt-get install libcairo2-dev // pkg-config -- cflags -- libs cairo //-I/usr/include/cairo-I/usr/include/glib-2.0-I /usr/lib/x86_64-linux-gnu/glib-2.0/include-I/usr/include/pixman-1-I/usr/include/freetype2-I/usr/include/libpng12-lcairo # include
Compilation in Ubuntu:
G ++ 'pkg-config -- cflags cairo 'test_cairo.cpp
Today, I have nothing to do with it. I 've been reading about it for a long time on my computer.
When I saw 43rd entries, I found that, as mentioned above, the algorithm replaces the manual loop.
No doubt arises.
I remember the operator [] operation (subscript operation) was the most efficient loop when I read the vector source code ).
The algorithm is fast.
The following is a test code:
// Test class and call Function
Class AAA{Public:Void MakeFul
C ++ Study Notes (15th): How the vector object grows in the memory space, learning notes vector
How does a vector object increase in memory?
We all know that vector objects are dynamically stored. From this point of view, they are a bit like linked lists, which can dynamically increase or decrease elements. We also kn
Vector series in practice c ++ -- use std: find and std: find_if algorithms for vector (custom class)
Previously, my blog talked about some usage of std: find and std: find _ if, but not about the custom class stored in the vector. How to Use std:: find and std: find_if?
First define a class:
class Item{private: std::string m_ItemId; int m_Price; int m_
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