string copy的用法

本文介绍了如何在C++中从字符串对象复制指定位置和长度的字符序列到目标数组,详细解释了参数作用及实现过程。

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Copy sequence of characters from string

Copies a substring of the current value of the string object into the array pointed by s. This substring contains the len characters that start at position pos.

s
Pointer to an array of characters.
The array shall contain enough storage for the copied characters.
len
Number of characters to copy (if the string is shorter, as many characters as possible are copied).
pos
Position of the first character to be copied.
If this is greater than the  string length, it throws  out_of_range.
Note: The first character in the  string is denoted by a value of  0 (not  1).
// string::copy
#include <iostream>
#include <string>

int main ()
{
  char buffer[20];
  std::string str ("Test string...");
  std::size_t length = str.copy(buffer,6,5);
  buffer[length]='\0';
  std::cout << "buffer contains: " << buffer << '\n';
  return 0;
}


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