Find the length of a String

Given a string str, the task is to find the length of the string.

Examples:

Input: str = “Geeks”
Output: Length of Str is : 5

Input: str = “GeeksforGeeks”
Output: Length of Str is: 13

Approach 1: Iterative(using Loop)

The most traditional method of finding the length of the string is by traversing each character through the loop.

• Using a counter, traverse each character of the string with the help of Loop.
• Update the counter for every character
• When the string is terminated or a null character is identified, break the loop.
• Return the counter value as the length of the string.

Below is the implementation of the above method:

C++

// C++ program to find length
// of a string
#include <bits/stdc++.h>
using namespace std;

// Driver code
int main()
{

    // String obj
    string str = "GeeksforGeeks";

    // The constructor of string will set
    // it to the C-style string,
    // which ends at the '\0'

    // size of string object Using while loop

    // while 'NOT NULL'
    int i = 0, cnt = 0;
    while (str[i]) {
        i++;
        cnt++;
    }
    cout << cnt << endl;

    return 0;
}

C

// C program to find the length of string
#include <stdio.h>
#include <string.h>

int main()
{
    char Str[] = "GeeksforGeeks";
    int i = 0, cnt = 0;

    while (Str[i]) {
        cnt++;
        i++;
    }

    printf("%d", cnt);

    return 0;
}

Java

public class StringLength {
    public static void main(String[] args) {
        // String object
        String str = "GeeksforGeeks";

        // Initialize a variable to count the characters
        int i = 0, cnt = 0;

        // Use a while loop to iterate through the characters until the end of the string
        while (i < str.length()) {
            i++;
            cnt++;
        }

        // Print the length of the string
        System.out.println(cnt);
    }
}

Python3

# Python program to find length
# of a string

# String obj
str = "GeeksforGeeks"

# size of string object Using while loop

i = 0
cnt = 0
while str[i:]:
    i += 1
    cnt += 1
print(cnt)

C#

using System;

class Program {
    static void Main(string[] args) {
        // String object
        string str = "GeeksforGeeks";

        // Use the Length property to get the length of the string
        int length = str.Length;

        // Print the length of the string
        Console.WriteLine(length);
    }
}

Javascript

// String object
let str = "GeeksforGeeks";

// Initialize a variable to count the characters
let i = 0, cnt = 0;

// Use a while loop to iterate through the characters until the end of the string
while (str[i] !== undefined) {
    i++;
    cnt++;
}

// Print the length of the string
console.log(cnt);

Output

13

Time Complexity: O(N), where N is the length of the string.
Auxillary space: O(1)

Approach 2: Using In-built methods

Every programming language offers a built-in method as well to find the length of the string, such as:

Programming Language	In-Built method to find the length of the string
C	strlen()
C++	size()
Java	length()
Python	len()
Javascript	length
C#	length()

Below is the implementation of the above methods:

C++

// C++ program to find length
// of a string
#include <iostream>
#include <string.h>
using namespace std;

// Driver code
int main()
{
    // String obj
    string str = "GeeksforGeeks";

    // size of string object using size() method
    cout << str.size() << endl;

    return 0;
}

C

// C program to find the length of
// string using strlen function
#include <stdio.h>
#include <string.h>

int main()
{
    char Str[] = "GeeksforGeeks";

    printf("%ld", strlen(Str));

    return 0;
}

Java

/*package whatever //do not write package name here */

import java.io.*;

class GFG {
    public static void main(String[] args)
    {
        String str = "GeeksforGeeks";
        int stringSize = str.length();
        System.out.println(stringSize);
    }
}

Python

# Python code to demonstrate string length
# using len

str = "GeeksforGeeks"
print(len(str))

C#

using System;

class Program
{
    static void Main()
    {
        // String variable
        string str = "GeeksforGeeks";

        // Length of the string using the Length property
        Console.WriteLine(str.Length);

        // Alternatively, you can also use the String.Length method:
        // Console.WriteLine(str.Length);

        // Pause the program execution to see the result
        Console.ReadLine();
    }
}
//Contributed by Aditi Tyagi

Javascript

// String object
let str = "GeeksforGeeks";

// Use the `length` property of the string object to get its length
// The `length` property directly gives the length of the string
let length = str.length;

// Print the length of the string
console.log(length);

Output

13

Time Complexity: O(1), except strlen() for C it is O(N)
Auxillary Space: O(1)