Iterate over characters of a string in C++

Given a string str of length N, the task is to traverse the string and print all the characters of the given string.

For Example:

#include <bits/stdc++.h>
using namespace std;

int main() {
    string str = "GeeksforGeeks";
    
    int N = str.length();
    for (int i = 0; i < N; i++) {
        cout<< str[i]<< " ";
    }
}

G e e k s f o r G e e k s 

Explanation: The program iterates over the string str using a for loop from index 0 to N - 1, where N is the length of the string. In each iteration, the character at index i (str[i]) is accessed and printed followed by a space.

Let's look at some other ways of doing it in C++:

1. Using "auto" keyword

The string can be traversed using auto iterator.

#include <bits/stdc++.h>
using namespace std;

int main(){
    string str = "GeeksforGeeks";
    int N = str.length();
   for (auto &ch : str) {
        cout<< ch<< " ";
    }
    return 0;
}

G e e k s f o r G e e k s 

Explanation:

• The string str stores "GeeksforGeeks".
• "auto" automatically detects the type of ch as char.
• "auto &ch" means each character is accessed by reference from the string.
• The range-based loop prints every character of the string with a space.

2. Using Iterator

The string can be traversed using iterator.

#include <bits/stdc++.h>
using namespace std;

int main(){
    string str = "GeeksforGeeks";
    int N = str.length();

    string::iterator it;
    for (it = str.begin(); it != str.end(); it++) {
        cout << *it << " ";
    }

    return 0;
}

G e e k s f o r G e e k s

Explanation:

• "string::iterator it", declares an iterator that points to characters in the string.
• "str.begin()" returns an iterator to the first character of the string.
• "str.end()" returns an iterator to the position after the last character.
• The for loop moves the iterator from start to end using "it++".
• "*it" dereferences the iterator to access and print each character.