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# std::getline

From cppreference.com
< cpp‎ | string‎ | basic string

Defined in header `<string>` |  |
template< class CharT, class Traits, class Allocator > std::basic_istream<CharT,Traits>& getline( std::basic_istream<CharT,Traits>& input, std::basic_string<CharT,Traits,Allocator>& str, CharT delim ); | (1) |
template< class CharT, class Traits, class Allocator > std::basic_istream<CharT,Traits>& getline( std::basic_istream<CharT,Traits>&& input, std::basic_string<CharT,Traits,Allocator>& str, CharT delim ); | (1) | (since C++11)
template< class CharT, class Traits, class Allocator > std::basic_istream<CharT,Traits>& getline( std::basic_istream<CharT,Traits>& input, std::basic_string<CharT,Traits,Allocator>& str ); | (2) |
template< class CharT, class Traits, class Allocator > std::basic_istream<CharT,Traits>& getline( std::basic_istream<CharT,Traits>&& input, std::basic_string<CharT,Traits,Allocator>& str ); | (2) | (since C++11)

`getline` reads characters from an input stream and places them into a string:

1) Behaves as `UnformattedInputFunction`, except that `input.gcount()` is not affected. After constructing and checking the sentry object, performs the following:
1) Calls str.erase()
2) Extracts characters from `input` and appends them to `str` until one of the following occurs (checked in the order listed)
a) end-of-file condition on `input`, in which case, `getline` sets `eofbit`.
b) the next available input character is `delim`, as tested by Traits::eq(c, delim), in which case the delimiter character is extracted from `input`, but is not appended to `str`.
c) str.max_size() characters have been stored, in which case `getline` sets `failbit` and returns.
3) If no characters were extracted for whatever reason (not even the discarded delimiter), `getline` sets `failbit` and returns.
2) Same as getline(input, str, input.widen(’\n’)), that is, the default delimiter is the endline character.

### [edit] Parameters

input | - | the stream to get data from
str | - | the string to put the data into
delim | - | the delimiter character

### [edit] Return value

`input`

### [edit] Notes

When used immediately after whitespace-delimited input, e.g. after int n; std::cin >> n;, `getline` consumes the endline character left on the input stream by operator>>, and returns immediately. A common solution is to ignore all leftover characters on the line of input with cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); before switching to line-oriented input.

### [edit] Example

The following example demonstrates how to use `getline` function to read user's input and how to process file line by line.

Run this code

    #include <string>
    #include <iostream>
    #include <sstream>

    int main()
    {
        // greet the user
        std::string name;
        std::cout << "What is your name? ";
        std::getline(std::cin, name);
        std::cout << "Hello " << name << ", nice to meet you.\n";

        // read file line by line
        std::istringstream input;
        input.str("1\n2\n3\n4\n5\n6\n7\n");
        int sum = 0;
        for (std::string line; std::getline(input, line); ) {
            sum += std::stoi(line);
        }
        std::cout << "\nThe sum is: " << sum << "\n";
    }

Possible output:

    What is your name? John Q. Public
    Hello John Q. Public, nice to meet you.

    The sum is 28

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