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Count of sub-strings of length n possible from the given string

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  • Last Updated : 07 May, 2021

Given a string str and an integer N, the task is to find the number of possible sub-strings of length N.
Examples: 
 

Input: str = “geeksforgeeks”, n = 5 
Output:
All possible sub-strings of length 5 are “geeks”, “eeksf”, “eksfo”, 
“ksfor”, “sforg”, “forge”, “orgee”, “rgeek” and “geeks”.
Input: str = “jgec”, N = 2 
Output:
 

 

Approach: The count of sub-strings of length n will always be len – n + 1 where len is the length of the given string. For example, if str = “geeksforgeeks” and n = 5 then the count of sub-strings having length 5 will be “geeks”, “eeksf”, “eksfo”, “ksfor”, “sforg”, “forge”, “orgee”, “rgeek” and “geeks” which is len – n + 1 = 13 – 5 + 1 = 9.
Below is the implementation of the above approach: 
 

C++




// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
 
// Function to return the count of
// possible sub-strings of length n
int countSubStr(string str, int n)
{
    int len = str.length();
    return (len - n + 1);
}
 
// Driver code
int main()
{
    string str = "geeksforgeeks";
    int n = 5;
 
    cout << countSubStr(str, n);
 
    return 0;
}

Java




// Java implementation of the approach
import java.util.*;
 
class GFG
{
 
// Function to return the count of
// possible sub-strings of length n
static int countSubStr(String str, int n)
{
    int len = str.length();
    return (len - n + 1);
}
 
// Driver code
public static void main(String args[])
{
    String str = "geeksforgeeks";
    int n = 5;
 
    System.out.print(countSubStr(str, n));
}
}
 
// This code is contributed by mohit kumar 29

Python3




# Python3 implementation of the approach
 
# Function to return the count of
# possible sub-strings of length n
def countSubStr(string, n) :
 
    length = len(string);
    return (length - n + 1);
 
# Driver code
if __name__ == "__main__" :
 
    string = "geeksforgeeks";
    n = 5;
 
    print(countSubStr(string, n));
     
# This code is contributed by Ryuga

C#




// C# implementation of the approach
using System;
 
class GFG
{
 
// Function to return the count of
// possible sub-strings of length n
static int countSubStr(string str, int n)
{
    int len = str.Length;
    return (len - n + 1);
}
 
// Driver code
public static void Main()
{
    string str = "geeksforgeeks";
    int n = 5;
 
    Console.WriteLine(countSubStr(str, n));
}
}
 
// This code is contributed by Code_Mech.

PHP




<?php
// PHP implementation of the approach
 
// Function to return the count of
// possible sub-strings of length n
function countSubStr($str, $n)
{
    $len = strlen($str);
    return ($len - $n + 1);
}
 
// Driver code
$str = "geeksforgeeks";
$n = 5;
 
echo(countSubStr($str, $n));
 
// This code is contributed by Code_Mech.
?>

Javascript




<script>
  // JavaScript implementation of the approach
  // Function to return the count of
  // possible sub-strings of length n
  function countSubStr(str, n) {
    var len = str.length;
    return len - n + 1;
  }
 
  // Driver code
  var str = "geeksforgeeks";
  var n = 5;
 
  document.write(countSubStr(str, n));
</script>

Output: 

9

 


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