Copy length of characters from array to std::string - c++

Question

I am trying to copy 5 characters from a character array into a std::string
char name[] = "Sally Magee";
std::string first;
copy(name, name + 5, first.begin()); //from #include <algorithm>
std::cout << first.c_str();
However I get the string plus a whole bunch of unprintable characters that I do not want. Any ideas? Thanks.

Answer 1

Just do
char name[] = "Sally Magee";
std::string first(name, name + 5);
std::cout << first << std::endl;
see std::string constructor link

Answer 2

What the std::copy algorithm does is to copy one source element after the other, and advance the destination iterator after each element.
This assumes that
either the size of the destination container has been set large enough to fit all the elements you copy,
or you use an iterator type that increases the size of the destination container each time you make an assignment to it.
Therefore, if you want to use the std::copy algorithm, there are two ways of solving this:
Resize the string before making the copies:
#include <iostream>
#include <string>
#include <algorithm>
int main()
{
char source[] = "hello world";
std::string dest;
dest.resize(5);
std::copy(source,source+5,begin(dest));
std::cout << dest << std::endl;
return 0;
}
Using a back-insert iterator instead of the standard one:
#include <iostream>
#include <string>
#include <algorithm>
#include <iterator>
int main()
{
char source[] = "hello world";
std::string dest;
std::copy(source,source+5,std::back_inserter(dest));
std::cout << dest << std::endl;
return 0;
}
However, as pointed out by others, if the goal is simply to copy the first 5 characters into the string at initialization time, using the appropriate constructor is clearly the best option:
std::string dest(source,source+5);