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: 

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 

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)