Question

use java recursion

find # of times a substring is in a string but it has to be the exact same, no extra letters attached to it and capitalization matters.

input: school is boring with schooling and School

substring: school

output: 1

Answer 1

import java.util.*;
class Main 
{ 
    //recursive function to count occurance of substrig
    static int countSubstr(String str1, String str2) 
    { 
        //length of input string
        int n1 = str1.length(); 
        
        //length of substring
        int n2 = str2.length(); 
    
        //base case 
        if (n1 == 0 || n1 < n2) 
                return 0; 
    
        //recursive case 
        //checkes if the first substring match or not
        if (str1.substring(0, n2).equals(str2)) 
                return countSubstr(str1.substring(n2 - 1), str2) + 1; 
    
        //otherwise, return the count from the remaining index 
        return countSubstr(str1.substring(n2 - 1), str2); 
    } 

    //main function
    public static void main(String args[]) 
    { 
        //to store input string and substring
        String input, substring;
        Scanner sc = new Scanner(System.in);
        
        //input String
        System.out.print("Input: ");
        input = sc.nextLine();
        
        
        //substring
        System.out.print("substring: ");
        substring = sc.nextLine();
        
        int count = countSubstr(input, substring);
        //function call and prints counts
        System.out.println("output: " + count);
    } 
} 

Please refer below screenshot of code for better understanding of indentation.

Sample output :