C++ Exercises: Find the length of a string without using the library function

Last update on August 14 2025 12:55:17 (UTC/GMT +8 hours)

34. Find the Length of a String Without Using Library Functions

Write a program in C++ to find the length of a string without using the library function.

Visual Presentation:

C++ Exercises: Find the length of a string without using the library function

Sample Solution:-

C++ Code :

#include <iostream> // Include the input/output stream library
#include <string>   // Include the string handling library
using namespace std; // Using standard namespace

int main() // Main function where the execution of the program starts
{
    char str1[50]; // Declare a character array to store the string
    int i, l = 0; // Declare integer variables i (for iteration) and l (for counting length)

    // Display message asking for input
    cout << "\n\n Find the length of a string:\n";
    cout << "---------------------------------\n";
    cout << " Input a string: ";
    cin >> str1; // Read input string from user

    // Loop to count the number of characters in the string
    for (i = 0; str1[i] != '\0'; i++) {
        l++; // Increment the length counter for each character encountered
    }

    // Display the number of characters counted in the string
    cout << "The string contains " << l << " number of characters." << endl;
    cout << "So, the length of the string " << str1 << " is:" << l << endl;
}

Sample Output:

 Find the length of a string:                                          
---------------------------------                                      
 Input a string: w3resource.com                                        
The string contains 14 number of characters.                           
So, the length of the string w3resource.com is:14

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to calculate the length of an input string by iterating through it until the null terminator is encountered.
Write a C++ program that computes the length of a string without using the built-in strlen() function, using a loop instead.
Write a C++ program to determine the number of characters in a string by manually iterating over its array of characters.
Write a C++ program that reads a string and counts its characters without relying on any library function.

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