Java program to find substring in a user input string :
In this Java program, we will learn how to find one substring in a string. The user will first enter the string and then he will enter the substring . Our program will check if it exist in the string or not. If yes, it will print the index of the substring. Let’s take a look at the program first :
Java program :
import java.util.*;
public class Main {
public static void main(String[] args) {
//1
Scanner scanner = new Scanner(System.in);
String inputString;
String subString;
//2
System.out.println("Enter a string : ");
inputString = scanner.nextLine();
//3
System.out.println("Enter a substring to find in the string : ");
subString = scanner.next();
//4
int index = inputString.indexOf(subString);
//5
if (index != -1) {
System.out.println("Index of this word : " + index);
} else {
System.out.println("The input sub-string is not found in the string.");
}
}
}
Explanation :
The commented numbers in the above program denote the step numbers below :
-
Create one Scanner object to read all user inputs.Create string inputString to read and store the user input string and subString to store the sub-string.
-
Ask the user to enter a string. Read it and store it in inputString variable.
-
Ask the user to enter a substring. Read it and store it in subString variable.
-
Find out the first index of occurance of subString in inputString. If it is found , indexOf() will return the index number. Else, it will return -1.
-
Check the value of index and print out the index if found. Else print that no sub string was found.
Sample Output :
Enter a string :
Hello world
Enter a substring to find in the string :
world
Index of this word : 6
Enter a string :
Hello world
Enter a substring to find in the string :
earth
The input sub-string is not found in the string.