How do I iterate over the words of a string in C++?

To iterate over the words of a string in C++, you can use std::istringstream along with the extraction operator (>>), which splits the string by whitespace (spaces, tabs, newlines). Here’s a step-by-step solution:

1. Include Necessary Headers

#include <iostream>
#include <string>
#include <sstream> // Required for std::istringstream
using namespace std;

2. Use std::istringstream to Split the String

int main() {
    string input = "Hello   world  C++   programmers!";

    // Create a string stream from the input
    istringstream iss(input);

    string word;
    while (iss >> word) { // Extract words one by one
        cout << "Word: " << word << endl;
    }

    return 0;
}

Output

Word: Hello
Word: world
Word: C++
Word: programmers!

Key Notes:

• Whitespace Handling: The extraction operator (>>) automatically skips all whitespace (spaces, tabs, newlines).
• Edge Cases:
• Leading/trailing whitespace is ignored.
• Consecutive whitespace is treated as a single delimiter.
• Empty strings produce no output.

Alternative Method: Split by Custom Delimiters

If you need to split by a specific delimiter (e.g., commas), use std::getline with a delimiter:

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

int main() {
    string input = "apple,banana,cherry";
    char delimiter = ',';

    istringstream iss(input);
    string word;
    while (getline(iss, word, delimiter)) {
        cout << "Word: " << word << endl;
    }

    return 0;
}

Output

Word: apple
Word: banana
Word: cherry

Summary

Method	Behavior
>> Operator	Splits by any whitespace (default).
getline	Splits by a custom delimiter (e.g., ,, ;, etc.).

Choose the method based on whether you need to split by whitespace or a custom delimiter!