Reading a Full Line with std::getline()

Reading a full line of input, including spaces, is best done with std::getline().

Unlike the >> operator, which stops at spaces, std::getline() reads until it encounters a newline character, capturing all spaces in between. Here is an example:

1#include <iostream>
2#include <string>
3
4int main() {
5  std::string input;
6  std::cout << "Please provide input: ";
7  std::getline(std::cin, input);  
8  std::cout << "Input extracted: " << input;
9}

1Please provide input: Hello World from C++
2Input extracted: Hello World from C++

In this code, std::getline() reads everything the user types until they press Enter, storing the entire input line in the input string.

If you need to use a custom delimiter instead of the default newline character, you can specify the delimiter as a third argument to std::getline():

1#include <iostream>
2#include <sstream>
3#include <string>
4
5int main() {
6  std::string input = "Hello,World,from,C++";
7  std::istringstream stream(input);
8  std::string word;
9
10  while (std::getline(stream, word, ',')) {  
11    std::cout << "Extracted: " << word << '\n';
12  }
13}

1Extracted: Hello
2Extracted: World
3Extracted: from
4Extracted: C++

In this example, std::getline() reads from the std::istringstream stream and uses a comma as the delimiter, extracting words separated by commas.

• Reads entire lines, including spaces
• Allows for custom delimiters
• More control over input handling compared to >> operator

Using std::getline() ensures that you capture all the user's input, including spaces, making it ideal for processing full lines of text in C++.