给定字符串可能存在的长度为n的子字符串的计数

给定一个字符串str和一个整数N ，任务是找到长度为N的可能子字符串的数量。
例子：

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 
 

方法：长度为n的子字符串的计数将始终为len – n + 1 ，其中len是给定字符串的长度。例如，如果str =“geeksforgeeks”和n = 5则具有长度5将“爱好者”，“eeksf”的子串的计数，“eksfo”，“ksfor”，“sforg”，“锻造”，“ orgee”，‘rgeek’和‘这是len爱好者’ – N + 1 = 13 – 5 + 1 = 9。
下面是上述方法的实现：

C++

// C++ implementation of the approach
#include 
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.

Javascript

  // 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));

输出：

9

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