stl中copy()函数

C ++ STL std :: rotate_copy()函数 (C++ STL std::rotate_copy() function)

rotate_copy() function is a library function of algorithm header, it is used to rotate left the elements of a sequence within a given range and copy the rotating elements to another sequence, it accepts the range (start, end) of the input sequence, a middle point, and an iterator pointing to start element of result sequence. It rotates the elements in such a way that the element pointed by the middle iterator becomes the new first element.

rotation_copy()函数是算法标头的库函数，用于在给定范围内向左旋转序列的元素，并将旋转的元素复制到另一个序列，它接受输入序列的范围(开始，结束)，一个中间点，以及一个指向结果序列开始元素的迭代器。 它以使中间迭代器指向的元素成为新的第一个元素的方式旋转元素。

Note: To use rotate_copy() function – include <algorithm> header or you can simple use <bits/stdc++.h> header file.

注意：要使用rotate_copy()函数 –包括<algorithm>头文件，或者您可以简单地使用<bits / stdc ++。h>头文件。

Syntax of std::rotate_copy() function

std :: rotate_copy()函数的语法

    std::rotate_copy(
iterator start,
iterator middle,
iterator end,
iterator start_result);

Parameter(s):

参数：

• iterator start – an iterator pointing to the first element of the sequence.

  迭代器开始 –指向序列第一个元素的迭代器。

• iterator middle – an iterator pointing to the middle or any other elements from where we want to start the rotation.

  中间迭代器 –指向中间或我们要开始旋转的位置的任何其他元素的迭代器。

• iterator end – an iterator pointing to the last element of the sequence.

  迭代器末端 –指向序列的最后一个元素的迭代器。

• iterator start_result – an iterator pointing to the first element in result sequence.

  iterator start_result –指向结果序列中第一个元素的迭代器。

Return value: void – it returns noting.

返回值： void –返回注释。

Example:

例：

    Input:
//an array (source)
int arr[] = { 10, 20, 30, 40, 50 };
//vector
vector<int> v(5);
//rotating and copy array elements to the vector
rotate_copy(arr + 0, arr + 2, arr + 5, v.begin());
Output:
vector elements: 30 40 50 10 20

C ++ STL程序演示了std :: rotate_copy()函数的使用 (C++ STL program to demonstrate use of std::rotate_copy() function)

In this program, we have an array and a vector; we are rotating its elements from 2nd index and copying into the vector.

在这个程序中，我们有一个数组和一个向量。 我们将其元素从第二索引旋转并复制到向量中。

//C++ STL program to demonstrate use of
//std::rotate_copy() function
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
//main code
int main()
{//an array (source)
int arr[] = { 10, 20, 30, 40, 50 };
//vector
vector<int> v(5);
//printing array and vector elements
cout << "array elements..." << endl;
for (int x : arr)
cout << x << " ";
cout << endl;
cout << "vector elements begfore rotating..." << endl;
for (int x : v)
cout << x << " ";
cout << endl;
//rotating and copy array elements to the vector
rotate_copy(arr + 0, arr + 2, arr + 5, v.begin());
cout << "vector elements after rotating..." << endl;
for (int x : v)
cout << x << " ";
cout << endl;
return 0;
}

Output

输出量

array elements...
10 20 30 40 50
vector elements begfore rotating...
0 0 0 0 0
vector elements after rotating...
30 40 50 10 20

Reference: C++ std::rotate_copy()

参考： C ++ std :: rotate_copy()

翻译自: https://www.includehelp.com/stl/std-rotate_copy-function-with-example.aspx

stl中copy()函数