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法律研究在 C++ 中复制向量的办法
有不同的方式在 C++ 中复制一个向量。
1) std::copy
std:: copy 是一个复制一个向量到另一个向量的内置内容。
语法
std::copy(first_iterator_o, last_iterator_o, back_inserter()): first_iteratot_0 = First iterator of first vector. last_iteratot_0 = Last iterator of first vector. back_inserter() = To insert values from back.
算法
Begin Declare v1 of vector type. Initialize some values into v1 vector in array pattern. Declare v2 of vector type. Call copy(v1.begin(), v1.end(), back_inserter(v2)) to copy all elements of v1 to v2. Print “v1 vector elements are :”. for (int i=0;i<1.size; i++) print the all element of v2 vector. Print “v2 vector elements are :”. for (int i=0;i<2.size; i++) print the all element of v2 vector. End.
示例代码
#include<iostream>
#include<vector>
#include<algorithm> // for copy.
#include<iterator> // for back_inserter
using namespace std;
int main() {
vector<int> v1{ 7, 6, 4, 5 };
vector<int> v2;
copy(v1.begin(), v1.end(), back_inserter(v2));
cout << "v1 vector elements are : ";
for (int i=0; i<v1.size(); i++)
cout << v1[i] << " ";
cout << endl;
cout << "v2 vector elements are : ";
for (int i=0; i<v2.size(); i++)
cout << v2[i] << " ";
cout<< endl;
return 0;
}输出
v1 vector elements are : 7 6 4 5 v2 vector elements are : 7 6 4 5
2) 分配运算符
这也被用于从向量 1 到向量 2 复制值。
语法
std::assign(first_iterator_o, last_iterator_o): first_iteratot_0 = First iterator of first vector. last_iteratot_0 = Last iterator of first vector.
算法
Begin Initialize a vector v1 with its elements. Declare another vector v2. Call assign() to copy the elements of v1 to v2. Print the elements of v1. Print the elements of v2. End.
示例代码
#include<iostream> #include<vector> // for vector #include<iostream>
#include<vector>// for vector
#include<algorithm>// for copy() and assign()
#include<iterator>// for back_inserter
using namespace std;
int main() {
vector<int> v1{7,6,4,5};
vector<int> v2;
v2.assign(v1.begin(), v1.end());
cout << "v1 vector elements are : ";
for (int i=0; i<v1.size(); i++)
cout << v1[i] << " ";
cout << endl;
cout << "v2 vector elements are : ";
for (int i=0; i<v2.size(); i++)
cout << v2[i] << " ";
cout<< endl;
return 0;
}输出
v1 vector elements are : 7 6 4 5 v2 vector elements are : 7 6 4 5
3) 使用赋值“=”运算符
这是一种从向量 1 到向量 2 复制值的简单方法。
算法
Begin Initialize a vector v1 with its elements. Declare another vector v2. Call assignment operator “=” to copy the elements of v1 to v2. Print the elements of v1. Print the elements of v2. End.
示例代码
#include<iostream>
#include<vector> // for vector
#include<algorithm>// for copy() and assign()
#include<iterator>// for back_inserter
using namespace std;
int main() {
vector<int> v1{7,6,4,5};
vector<int> v2;
v2 = v1 ;
cout << "v1 vector elements are : ";
for (int i=0; i<v1.size(); i++)
cout << v1[i] << " ";
cout << endl;
cout << "v2 vector elements are : ";
for (int i=0; i<v2.size(); i++)
cout << v2[i] << " ";
cout<< endl;
return 0;
}输出
v1 vector elements are : 7 6 4 5 v2 vector elements are : 7 6 4 5
4) 使用 push_back 方法
算法
Begin Initialize a vector v1 with its elements. Declare another vector v2. Make a for loop to copy elements of first vector into second vector by Iterative method using push_back(). Print the elements of v1. Print the elements of v2. End.
示例代码
#include<iostream> #include<vector> // for vector
#include<iostream>
#include<vector>// for vector
#include<algorithm>// for copy() and assign()
#include<iterator>// for back_inserter
using namespace std;
int main() {
vector<int> v1{7,6,4,5};
vector<int> v2;
for (int i=0; i<v1.size(); i++)
v2.push_back(v1[i]);
cout << "v1 vector elements are : ";
for (int i=0; i<v1.size(); i++)
cout << v1[i] << " ";
cout << endl;
cout << "v2 vector elements are : ";
for (int i=0; i<v2.size(); i++)
cout << v2[i] << " ";
cout<< endl;
return 0;
}输出
v1 vector elements are : 7 6 4 5 v2 vector elements are : 7 6 4 5
5) 通过作为构造函数传递向量
算法
Begin Initialize a vector v1 with its elements. Declare another vector v2 and copying elements of first vector to second vector using constructor method and they are deeply copied. Print the elements of v1. Print the elements of v2. End.
示例代码
#include<iostream>
#include<vector>// for vector
#include<algorithm>// for copy() and assign()
#include<iterator>// for back_inserter
using namespace std;
int main() {
vector<int> v1{7,6,4,5};
vector<int> v2(v1);
cout << "v1 vector elements are : ";
for (int i=0; i<v1.size(); i++)
cout << v1[i] << " ";
cout << endl;
cout << "v2 vector elements are : ";
for (int i=0; i<v2.size(); i++)
cout << v2[i] << " ";
cout<< endl;
return 0;
}输出
v1 vector elements are : 7 6 4 5 v2 vector elements are : 7 6 4 5
更新于： 30-7-2019
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