C++ getline()

In C++, the getline() function converts user input into a character-delimited string and stores it into a variable. If a delimiting character is not specified, then the input is stored until \n (newline) is encountered. This function is widely used in reading multi-word user input, processing lines from text files, and parsing structured data such as CSV records or configuration files where input must be read line-by-line.

Syntax

The getline() function is defined in the <string> header:

getline(cin, string, delim)

Parameters:

• cin: The object in the stream, which would be the user input.
• string: Refers to the variable to which the user input is set.
• delim (Optional): Refers to a character the user input is stored up to.

Although not recommended in C++, since it deals with C strings, getline() can be called on the cin object as a member function like this:

cin.getline(string, length, delim)

Parameters:

• string: Refers to the variable to which the user input is set.
• length: The maximum number of characters to read, including the null terminator.
• delim (Optional): Refers to a character the user input is stored up to.

Example 1: Using getline() Without delim

This example demonstrates the usage of the getline() function without the delim parameter:

#include <iostream>
#include <string>

using namespace std;

int main() {
  // Create a string
  string my_str;

  // Take input from the user
  cout << "Enter a pet name: ";

  // Store the input in the string
  getline(cin, my_str);

  cout << "My pet's name is " + my_str + "!";
}

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Here is the output if the user input is “Nimbus”:

Enter a pet name: Nimbus
My pet's name is Nimbus!

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Example 2: Using getline() with delim

This example demonstrates the usage of the getline() function with the delim parameter:

#include <iostream>
#include <string>

using namespace std;

int main() {
  // Create a string
  string my_str;

  // Take input from the user
  cout << "Enter a pet name: ";

  // Store the input in the string until '\n' (newline) is encountered
  getline(cin, my_str, '\n');

  cout << "My pet's name is " + my_str + "!";
}

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Here is the output if the user input is “Dora”:

Enter a pet name: Dora
My pet's name is Dora!

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Codebyte Example: Using getline() on cin

This codebyte example applies the getline() function on the cin object:

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getline() vs cin

Frequently Asked Questions

1. Can getline() read input from files?

Yes, getline() works with any input stream, including file streams (std::ifstream).

2. Does getline() include the newline character (\n) in the string?

No, getline() stops reading at the newline but does not store it in the string. The result is a clean line without the \n.

3. Can I use a custom delimiter with getline()?

Yes, you can specify a delimiter:

std::getline(std::cin, str, ';'); // Stops at semicolon instead of newline

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This is useful for parsing CSV or semi-colon-separated input.