The length of a string using pointers

Write a program to find the length of a string using pointers. Examples:

Input : given_string = “geeksforgeeks”
Output : length of the string = 13

Input : given_string = “coding”
Output : length of the string = 6

Prerequisite : Pointer in C 

Approach Used : In this program we make use of * operator. The * (asterisk) operator denotes the value of variable . The * operator at the time of declaration denotes that this is a pointer, otherwise it denotes the value of the memory location pointed by the pointer. In the below program, in string_length function we check if we reach the end of the string by checking for a null represented by ‘\0’ . 

CPP

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

// function to find the length
// of the string through pointers
int string_length(char* given_string)
{
    // variable to store the
    // length of the string
    int length = 0;
    while (*given_string != '\0') {
        length++;
        given_string++;
    }

    return length;
}

// Driver function
int main()
{
    // array to store the string
    char given_string[] = "geeksforgeeks";
    cout << string_length(given_string);
    return 0;
}

Output:

13

Time Complexity: O(N)
Auxiliary Space: O(1)

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