Count Sub String Occurrence Algorithm With Example using JAVA

Count Sub String Occurrence Algorithm With Example using JAVA

Sub String Occurrence count means to check how many  times a particular  part of a string repeat in the given string.

Algorithm:

step 1: get the length of MainString and SubString variables and initialize i=j=count=0;

            ex:

            len1=mainString.length();

            len2=subString.length();

Step 2: start loop from i=0 to len1-len2;

            initialize the j with 0 and flag with true;

Step 3: check whether character of mainString at position i is equals to character of SubString at position j ?

             ex:

             if(mainString.charAt(i)==subString.charAt(j))

Step 4: if both are sem then start another loop with j=1 and j is j<=subString.length(); now check whether the character of mainString at position i+j is not Equals to character of SubString at position j. then make the flag = false and break the loop.

           ex:

           for(j=1;j<=SubString.length();j++){

                         if(mainString.charAt(i+j)!=subString(j)){

                                     flag=false;

                                       break;

                          }

            }

Step 5:out side the inner for loop check whether the flag value is true if yes then count= count+1

            ex:

            if(flag)

               count++;

Download Program: Click Here

Program:

import java.util.*;

public class reverse{

public static int getSubString(String mainString,String subString){

int max=1+mainString.length()-subString.length();

int count=0;

for(int i=0;i<max;i++){

boolean flag=true;

int j=0;

if(mainString.charAt(i)==subString.charAt(j)){

for(j=1;j<subString.length();j++){

if(mainString.charAt(i+j)!=subString.charAt(j)){

flag=false;

break;

}

}

}else

flag=false;

if(flag)

count++;

}

return count;

}

public static void main(String [] args){

Scanner input=new Scanner(System.in);

System.out.print("Enter Main String:");

String mainString=input.nextLine();

System.out.print("Enter Sub String :");

String subString=input.nextLine();

int count=getSubString(mainString,subString);

System.out.println("String Found:"+count);

}

}

compile the above code:javac subStringcounter.java

To Run the code: java subStringcounter

Output: