CppHow-ToBeginner · 3 min read

How to Use getline in C++: Syntax and Examples

In C++, use std::getline to read an entire line of text from an input stream like std::cin. It reads characters until it finds a newline, storing the result in a std::string. This is useful for reading input with spaces.

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Syntax

The basic syntax of std::getline is:

std::getline(input_stream, string_variable);

Here, input_stream is usually std::cin or any input stream, and string_variable is a std::string where the line will be stored.

Optionally, you can specify a delimiter character to stop reading before it:

std::getline(input_stream, string_variable, delimiter);

cpp

std::getline(std::cin, line);
std::getline(std::cin, line, '\n');

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Example

This example shows how to use std::getline to read a full line of text including spaces from the user and then print it.

cpp

#include <iostream>
#include <string>

int main() {
    std::string line;
    std::cout << "Enter a full line of text:\n";
    std::getline(std::cin, line);
    std::cout << "You entered: " << line << std::endl;
    return 0;
}

Output

Enter a full line of text: Hello world from C++ You entered: Hello world from C++

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Common Pitfalls

One common mistake is mixing std::cin >> with std::getline without clearing the input buffer. The >> operator leaves the newline character in the input, so std::getline reads an empty line immediately.

To fix this, use std::cin.ignore() to discard the leftover newline before calling std::getline.

cpp

#include <iostream>
#include <string>

int main() {
    int number;
    std::string line;

    std::cout << "Enter a number: ";
    std::cin >> number;
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // Clear newline left in buffer

    std::cout << "Enter a line of text: ";
    std::getline(std::cin, line);

    std::cout << "Number: " << number << std::endl;
    std::cout << "Line: " << line << std::endl;

    return 0;
}

Output

Enter a number: 42 Enter a line of text: Hello after number Number: 42 Line: Hello after number

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Quick Reference

Function: std::getline
Purpose: Read a full line from input stream into a string
Parameters: input stream, string variable, optional delimiter
Common use: Reading lines with spaces from std::cin
Remember: Use std::cin.ignore() after >> operator before std::getline

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Key Takeaways

Use std::getline to read entire lines including spaces from input streams.

Always store getline input in a std::string variable.

If mixing with std::cin >>, call std::cin.ignore() before getline to avoid empty input.

You can specify a delimiter character to stop reading before it.

getline reads until newline by default, making it ideal for line-based input.