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

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: 9 All possible sub-strings of length 5 are “geeks”, “eeksf”, “eksfo”, “ksfor”, “sforg”, “forge”, “orgee”, “rgeek” and “geeks”.Input: str = “jgec”, N = 2 Output: 3  
 
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++
Java
Python3
C#
PHP
Javascript
// C++ implementation of the approach#include <bits/stdc++.h>using namespace std; // Function to return the count of// possible sub-strings of length nint countSubStr(string str, int n){    int len = str.length();    return (len - n + 1);} // Driver codeint main(){    string str = "geeksforgeeks";    int n = 5;     cout << countSubStr(str, n);     return 0;}
// Java implementation of the approachimport java.util.*; class GFG{ // Function to return the count of// possible sub-strings of length nstatic int countSubStr(String str, int n){    int len = str.length();    return (len - n + 1);} // Driver codepublic 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 implementation of the approach # Function to return the count of# possible sub-strings of length ndef countSubStr(string, n) :     length = len(string);    return (length - n + 1); # Driver codeif __name__ == "__main__" :     string = "geeksforgeeks";    n = 5;     print(countSubStr(string, n));     # This code is contributed by Ryuga
// C# implementation of the approachusing System; class GFG{ // Function to return the count of// possible sub-strings of length nstatic int countSubStr(string str, int n){    int len = str.Length;    return (len - n + 1);} // Driver codepublic static void Main(){    string str = "geeksforgeeks";    int n = 5;     Console.WriteLine(countSubStr(str, n));}} // This code is contributed by Code_Mech.
<?php// PHP implementation of the approach // Function to return the count of// possible sub-strings of length nfunction 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.?>
<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>
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mohit kumar 29
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