Prime Strings:
You must have heard about prime numbers. But have you ever thought about prime string?
It's very simple and interesting. Here's the explanation:-
In computer science, string is sequence of characters.Characters may be alphabets, numbers, punctuation, or special symbols.
So any word is a string. for example: "Hello" is a string.
Now, what is prime string? A string which cannot be constructed by concatenating two or more than two(multiple) equal strings.
Let's have a string "Road" , when we divide "road" into two equal parts we get "ro" and "ad" which are not equal strings. Thus "road" is a prime string.
Now let's take a string "baba". By dividing this string into two equal parts we get "ba" and "ba" . Both these strings are equal. So it is not a prime string.
Here's a prime string program written in java. It also tells the first half and second half of a string and whether it is prime or not.
import java.util.Scanner;
class PrimeString
{
public static void main(String args[])
{
Scanner input = new Scanner(System.in);
System.out.println("Enter the string to check whether it is prime or not?");
String s = input.next(); //Getting user input
int i,len = s.length(); //Find length of string
String s1 = "";
String s2 = "";
if((len % 2) != 0) //if length of string is odd then it would definitely be prime
System.out.println("The entered string is PRIME!");
else //if string's length is even
{
for(i=0;i<len/2;i++) //loop for seperating first half of string
s1 = s1 + (s.charAt(i));
for(i=len/2;i<len;i++) //loop for seperating second half of string
s2 = s2 + (s.charAt(i));
if(s1.equals(s2)) //if both parts are equal then string is not prime
System.out.println("The entered string is not PRIME!");
else //if they are different then string is prime
System.out.println("The entered string is PRIME!");
}
}
}
 |
| Output of the above program |
Thus a string whose two equal parts are not same is called a prime string.