Question

Need Help Please

Using Java Language

Create a Code

Write a class (and a client class to test it) that encapsulates the evolution of the passwords of three students over four months. Your only instance variable should be a two-dimensional array of values representing the passwords. Dimension 1 represents the student and dimension 2 represents the month. (Since we are concerned about security, we are assuming that people change their password once a month; we only care about the value of the password at the end of a given month.) Your constructor can simply take a single-dimensional array of words representing the 12 passwords; they can be assigned to the two-dimensional array elements one at a time, starting with the first row. You should include the following methods:

❑ a method returning the index of the person who changed his or her password the most times

❑ a method returning the longest password❑ a method changing all the passwords to “unlock”

❑ a method returning true if at least one person had a given word—the method’s parameter—as his/her password in at least one month; false otherwise

Answer 1

Source Code in Java:

class Password
{
String pass[][]; //instance variable
Password(String passwords[]) //parametrized constructor
{
pass=new String[3][4]; //initializing 2D array
for(int i=0;i<3;i++)
{
for(int j=0;j<4;j++)
pass[i][j]=passwords[i*4+j]; //storing names from the parameter array
}
}
int mostChanges() //method to return index of student with most changes in password
{
int max=0,index=0; //setting max index to 0 initially
for(int j=0;j<4-1;j++) //finding out changes for first index and setting it to max
{
if(pass[0][j].equals(pass[0][j+1])==false)
max++;
}
//finding out changes for rest of the indexes and comparing to temporary max
for(int i=1;i<3;i++)
{
int count=0;
for(int j=0;j<4-1;j++)
{
if(pass[i][j].equals(pass[i][j+1])==false)
count++;
}
if(count>max)
{
max=count;
index=i;
}
}
return index; //returning index with most changes
}
String largestPassword() //method to find and return the largest password
{
String largest=pass[0][0]; //storing first password as largest temporarily
for(int i=0;i<3;i++)
{
for(int j=0;j<4;j++)
{
if(pass[i][j].length()>largest.length())
largest=pass[i][j];
}
}
return largest; //returning largest password
}
void changeToUnlock() //method to change all passwords to unlock
{
for(int i=0;i<3;i++)
{
for(int j=0;j<4;j++)
pass[i][j]="unlock"; //changing all passwords in 2D array to "unlock"
}
}
boolean isPresent(String word) //method to check if a word was a password
{
for(int i=0;i<3;i++)
{
for(int j=0;j<4;j++)
{
if(pass[i][j].equals(word)) //checking every word
return true;
}
}
return false; //if program reaches this point, word was not found
}
}

class PasswordTest
{
public static void main(String args[])
{
//testing class Password
String passwords[]={"climate","climate","change","hiboys","lolitsme","lolitsstillme","lolitsnotme","heyboys","password123","password123","password123","password123"};
Password p=new Password(passwords);
System.out.println("Index of student with most changes: "+p.mostChanges());
System.out.println("Largest password: "+p.largestPassword());
p.changeToUnlock();
System.out.println("Largest password after changing all to unlock: "+p.largestPassword());
}
}

Output:

Blue): Terminal Window - Java Assignment Options Index of student with most changes: 1 Largest password: lolitsstillme Largest password after changing all to unlock: unlock