How to Iterate through a String word by word in C++

Given a String comprising of many words separated by space, the task is to iterate over these words of the string in C++.
Example:

Input: str = “GeeksforGeeks is a computer science portal for Geeks”
Output: GeeksforGeeks
             is
             a
             computer
             science
             portal
             for
             Geeks

Input: str = “Geeks for Geeks”
Output: Geeks
             for
             Geeks

Approach: istringstream class is best suitable for this purpose. When a string is given split by whitespace, this class can be used to easily fetch and use each word of the String.
Syntax:

string str = {"Geeks for Geeks"};
istringstream iss(str);

Below is the implementation of the above approach: 

CPP

// C++ program to Iterate through
// a String word by word

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

using namespace std;

// Driver code
int main()
{

    // Get the String
    string str = "GeeksforGeeks is a computer "
                 "science portal for Geeks";

    // Initialise the istringstream
    // with the given string
    istringstream iss(str);

    // Iterate the istringstream
    // using do-while loop
    do {
        string subs;

        // Get the word from the istringstream
        iss >> subs;

        // Print the word fetched
        // from the istringstream
        cout << subs << endl;

    } while (iss);

    return 0;
}

Output

GeeksforGeeks
is
a
computer
science
portal
for
Geeks

Another method: This can also be done iteratively

1. Calculate the length of the given string say n
2. Iterate on given string from i = 0 to i < n
3. Check if current character str[i] == ” ” or i == n – 1
   1. Print the string formed by word and empty the word string
4. Otherwise, keep appending characters in the word string

Below is the implementation of the 

C++

// C++ program to Iterate a string Word by Word
#include <bits/stdc++.h>
using namespace std;

// Function to split words from the given string.
void splitWord(string str)
{
    // Find length of given variable
    int n = str.length();

    // Create an empty string
    string word = "";

    // Iterate over the string character by character using
    // For loop
    for (int i = 0; i < n; i++) {

        // Check if the current iteration is equal to ' ' or
        // it's the last character
        if (str[i] == ' ' or i == (n - 1)) {

            // Print word
            cout << word + str[i] << endl;
            word = "";
        }

        // Add current character in word string
        else {
            word += str[i];
        }
    }
}

int main()
{
    // Given string
    string str = "GeeksforGeeks is a computer "
                 "science portal for Geeks";

    splitWord(str);

    return 0;
}
// This code is contributed by Shivesh Kumar Dwivedi

Output

GeeksforGeeks 
is 
a 
computer 
science 
portal 
for 
Geeks

Time Complexity: O(n), Where n is the size of the given string
Auxiliary Space: O(1)