Question

c+中copy（）函数有什么用，用到什么头文件

c+中copy（）函数有什么用，用到什么头文件

Answer 1

1. 包含以下头文件：

#include <algorithm>

2. 含义：

output_iterator copy( input_iterator start, input_iterator end, output_iterator dest );
The copy function copies the elements between start and end to dest. In other words, after copy has run,

*dest = *start
*(dest+1) = *(start+1)
*(dest+2) = *(start+2)
...
*(dest+N) = *(start+N)
The return value is the position in the destination range after the last element copied (i.e. dest+N+1). copy runs in linear time.

3. 程序举例:

For example, the following code uses copy to both copy the contents of one vector to another and to display the resulting vector:

vector<int> from_vector;
for( int i = 0; i < 10; i++ ) {
from_vector.push_back( i );
}

vector<int> to_vector(10);

copy( from_vector.begin(), from_vector.end(), to_vector.begin() );

cout << "to_vector contains: ";
copy( to_vector.begin(), to_vector.end(), ostream_iterator<int>( cout, " " ) );

cout << endl;

Answer 2

一般是在字符串中用到strcpy()函数，头文件一般是#include<string.h>。

Answer 3

size_type
copy(
char
*str,
size_type
num,
size_type
index
);
copy()函数拷贝自己的num个字符到str中（从索引index开始）。返回值是拷贝的字符数