Create a text file that stores a list of user names and their associated passwor
ID: 3673270 • Letter: C
Question
Create a text file that stores a list of user names and their associated passwords. Write a Java program that will ask a user to enter their username and password and compares against the ones stored in the file. If their is a match, print "Access Granted" or else print "Access Denied". Make sure that the password is case sensitive. In case there isn't a match,the user gets two more attempts. If the user input doesn't match in all the three attempts, your program should display "Three failed attempts, your account has been locked"
Explanation / Answer
/**
* The java program PasswordMatching that prompts user to enter
* the name and password . If user name and password are matched
* print "Access Granted " otherwise print "Access Denied".
* Allow user to enter two more trials . If failed to enter
* correct password , the print that account has been locked.
* **/
//PasswordMatching.java
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class PasswordMatching
{
public static void main(String[] args)
{
//set number of lines in the text file
final int LINES=4;
//text file name
String fileName="passwords.txt";
//create keyboard object
Scanner keyboard=new Scanner(System.in);
Scanner filereader=null;
int row=0;
//Create a 2D array of type String
String[][] passwords=new String[LINES][2];
//Open file in try catch block
try
{
//Create an instance of Scanner class to read file
filereader=new Scanner(new File(fileName));
//read file into array passwords
while(filereader.hasNextLine())
{
//read name from text file
String name=filereader.next();
//read password from text file
String password=filereader.next();
//set name and passwords in a passwords 2D array
//of 4 rows and 2 columns
passwords[row][0]=name;
passwords[row][1]=password;
//increment row by one
row++;
}
//close the filereader object
filereader.close();
}
//Catch the exception if file not found
catch (FileNotFoundException e)
{
System.out.println("File not found.");
}
int CHOICES=3;
int trials=1;
boolean found=false;
//Run while loop until trials are less than or equal to three
//and found is false
while(trials<=CHOICES &&!found)
{
System.out.println("Enter user name ");
//read userName
String userName=keyboard.nextLine();
System.out.println("Enter password ");
//user password
String password=keyboard.nextLine();
found=false;
for (int i = 0; i < passwords.length && !found; i++)
{
if(passwords[i][0].equals(userName)
&& passwords[i][1].equals(password))
{
//set found true
found=true;
}
}
//Check if found is true
if(found)
System.out.println("Access Granted");
else
System.out.println("Access Denied");
//increment the number of trials by one
trials++;
}
//print message if found is false and trials are three
if(!found && trials==3)
System.out.println("Three failed attempts, your account has been locked");
}
}
------------------------------------------------------------------------------------------------
Sample Input file
passwords.txt
johnson 1234
karan 4567
Kete 3242
Micheal 9009
--------------------------------------------------------------------------------------------------------------------
Sample Output:
Enter user name
johson
Enter password
1235
Access Denied
Enter user name
johson
Enter password
3456
Access Denied
Enter user name
johnson
Enter password
1234
Access Granted