Java while loop get longest common prefix between two String values

Question

We would like to write a program that prompts the user to enter two strings

Display the largest common prefix of the two strings.

Here are some sample runs: 

Enter the first string: Welcome to C++ 

Enter the second string: Welcome to programming 
The common prefix is Welcome to 

Enter the first string: food
Enter the second string: care

food and care have no common prefix 


import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);

    // Prompt the user to enter two strings
    System.out.print("Enter the first string: ");
    String string1 = input.nextLine();
    System.out.print("Enter the second string: ");
    String string2 = input.nextLine();

    //your code here
  }/*  ww w  .j a v a  2  s.c o  m*/
}






import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);

    // Prompt the user to enter two strings
    System.out.print("Enter the first string: ");
    String string1 = input.nextLine();
    System.out.print("Enter the second string: ");
    String string2 = input.nextLine();

    int index = 0;        // Initialize index to 0
    String prefix = "";    // Initialize prefix as empty string

    // Get the largest commmon prefix of the two strings
    while (string1.charAt(index) == string2.charAt(index)) {
      prefix += string1.charAt(index);
      index++;
    }

    // Display the result
    if (prefix.length() > 0)
      System.out.println("The commmon prefix is " + prefix);
    else
      System.out.println(string1 + " and " + string2 +
        " have no commmon prefix");
  }
}



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