Answer:
I am writing a JAVA program:
import java.util.Scanner; //used to take input from user
public class Main{
public static void function(String word){ //function that takes a word as parameter an applies a pattern
int count=0; // count the number of characters between first and last characters of the word string
char first = word.charAt(0); //gets the first character of the word
char last = word.charAt(word.length() - 1); /gets the last character
for(int i = 1; i<word.length()-1;i++) //iterates through word to count the characters between first and last characters
{ count=i; } //sets the count of characters to count variable
System.out.println(first+""+count+""+last); } //prints the first and last characters of input word with the number of characters between first and last characters of word string
public static void main(String []args){//start of main function
Scanner input= new Scanner(System.in); //creates Scanner class object
System.out.print("Enter a word: "); // prompts user to enter a word
String str= input.nextLine(); //reads word string from user
function(str); } } //calls function passing the string to it
Explanation:
I will explain the program with the help of an example:
Suppose the word is printer.
charAt(0) returns the character at the 0-th index of a string word i.e printer. This means the first character of "printer" is returned i.e. 'p'
word.charAt(word.length() - 1) returns the character at the word.length() - 1 index of a string word i.e printer. This means the last character of "printer" is returned i.e. 'r'. Here length() function is used to return the length of the string. The length of "printer" is 7 (from 0 to 6) so word.length() -1 returns 7-1 = 6. This means the character at 6th index.
for(int i = 1; i<word.length()-1;i++) loop counts the character between the first and last character of "printer" . It works as follows:
1st iteration:
i = 1
i<word.length()-1 is true because 1<6
count = i
count = 1
i = i + 1
i = 2
2nd iteration:
i = 2
i<word.length()-1 is true because 2<6
count = i
count = 2
i = i + 1
i = 3
3rd iteration:
i = 3
i<word.length()-1 is true because 3<6
count = i
count = 3
i = i + 1
i = 4
4th iteration:
i = 4
i<word.length()-1 is true because 4<6
count = i
count = 4
i = i + 1
i = 5
5th iteration:
i = 5
i<word.length()-1 is true because 5<6
count = i
count = 5
i = i + 1
i = 6
At next iteration i<word.length()-1 evaluates to false because i = 6
So final value of count is:
count = 5
System.out.println(first+""+count+""+last); statement prints the first character of "printer" i.e. 'p', followed by value of count i.e. 5 , followed by last character of "printer" i.e. 'r'
Output:
p5r
