getline question

[chipp]

i have a question about getline, to where the function return the value? for example:

#include <iostream>
#include <string>
using namespace std;

int main () {
  string str;
  cout << "Please enter full name: ";
  //doesn't have a storage variable
  getline (cin,str);
  cout << "Thank you, " << str << ".\n";
}

where the return value stored? in the system?is that related to the istream type that returned from the getline?

[Peter87]

getline returns a reference to the it's first argument (cin). This is useful so that you can easily check if the read was successful or not.

if (getline (cin,str))
{
	// the line was read without errors!
}

[Texan40]

getline() takes in a reference to a string in arugment 2 and fills it within the function. It returns the same istream reference that is passed in as argument 1. This return value is helpful for things like:

ifstream in("InputFile.txt");
if(in.good())
{
  std::string lineTmp;
  while(getline(in,lineTmp))
  {
    // process line string...
  }
}

When the stream has an error, or hits eof, it will break out of the while loop.

[vlad from moscow]

The std::getline function which you are using has the following declaration

template<class charT, class traits, class Allocator>

basic_istream<charT,traits>&
getline(basic_istream<charT,traits>& is, basic_string<charT,traits,Allocator>& str, charT delim);

So it returns a reference to input stream. At the same time it reads data in the string object that you are passing to it by reference.

As a result you can nesting the function, for example, the following way

std::string str;
int x;

std::getline( std::cin, str ) >> x;

Or another example

std::string s1;
std:;string s2;

std::getline( std::getline( std::cin, str1 ), str2 );

[chipp]

so it just return the address and thus make the statement true or false? btw

std::string str;
int x;

std::getline( std::cin, str ) >> x;

is the cin is flushed so it can accept another entry?

[chipp]

hello?

[vlad from moscow]

It returns reference to the input stream which is the first parameter of the function.
So std::getline( std:;cin, str ) return std:;cin.

[chipp]

what about my "second last question"?

[vlad from moscow]

I showed you already an example! Why do you do not try it?!