1. Write a complete Java method called sumNums that takes no parameters and retu
ID: 3696992 • Letter: 1
Question
1. Write a complete Java method called sumNums that takes no parameters and returns an integer.
The method uses a do-while loop to ask the user to enter a series of positive integer values and keeps a running total.
Use a sentinel (-1) to allow the user to indicate when they are finished.
The method returns the total.
2. Write a complete Java method called checkPassword that takes a String as
a parameter (password) and returns a boolean. First, check that the password is
at least 8 characters long. Then use a while loop to check that the
password contains at least one digit. If the password has the correct length
and contains a digit, return true, otherwise return false
3. Write a complete Java method called authenticate that takes two Strings (username, password)
as parameters and returns a boolean. If the username parameter has the value "Chucky" and
the password parameter has the value "Cheese1", return true. Otherwise return false.
4. Write a complete Java method called getScoreSheet that takes two ints
as parameters (rows and columns) and constructs a 2-dimensional array
of doubles (calles scores) with a size based on the rows and columns parameters.
Use a nested loop to initialize each value in the array to 100.00.
The method returns the scores array.
5. Write a complete Java method called writeList that takes an ArrayList of Strings as a parameter
and writes each String as a line in a text file.
Make sure to handle the Exception that might be thrown and print the error message to the
command line.
Explanation / Answer
CalcOperations.java
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;
public class CalcOperations {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("----------sumNums()-----------");
int total = sumNums();
System.out.println("The total is : "+total);
Scanner scan = new Scanner(System.in);
System.out.println("----------checkPassword()-----------");
System.out.println("Enter Pasword : ");
String pass = scan.next();
boolean status = checkPassword(pass);
if(status)
System.out.println("Valid Password");
else
System.out.println("Invalid Password");
System.out.println("----------authenticate()-----------");
status = authenticate("Chucky", "Cheese1");
System.out.println("Authenticate : "+status);
System.out.println("----------getScoreSheet()-----------");
getScoreSheet(2, 2);
System.out.println("Done. 2-dimensional array initialized each value in the array to 100.00 ");
System.out.println("----------writeList()-----------");
ArrayList<String> list = new ArrayList<String>();
list.add("aaaa");
list.add("bbbb");
list.add("cccc");
list.add("dddd");
list.add("eeee");
writeList(list);
}
public static int sumNums(){
int total = 0;
int n = 0;
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a series of positive integer values (-1 to Quit):");
do{
n = scan.nextInt();
if(n == -1) break;
total = total + n;
}while(true);
return total;
}
public static boolean checkPassword (String password){
int n = password.length();
boolean found = false;
if(n >= 8){
int i = 0;
while(i <= n){
if(Character.isDigit(password.charAt(i))){
found = true;
break;
}
i++;
}
return found;
}
else
return false;
}
public static boolean authenticate (String username, String password){
if(username.equals("Chucky") && password.equals("Cheese1")){
return true;
}
else{
return false;
}
}
public static double[][] getScoreSheet (int rows, int columns){
double scores[][]= new double[rows][columns];
for(int i=0; i<rows; i++){
for(int j=0; j<columns; j++){
scores[i][j] = 100.0;
}
}
return scores;
}
public static void writeList (ArrayList<String> list){
try{
String fileName = "list.txt";
File file = new File(fileName);
FileWriter fw = new FileWriter(file);
String s = "";
for(String str: list){
s = s + str +" ";
}
fw.write(s);
fw.flush();
fw.close();
System.out.println("Data has been saved in file");
}
catch(IOException e){
System.out.println("Error: "+e.toString());
}
}
}
Output:
----------sumNums()-----------
Please enter a series of positive integer values (-1 to Quit):
3
4
5
6
7
6
5
41
12
34
-1
The total is : 123
----------checkPassword()-----------
Enter Pasword :
Suresh12!@
Valid Password
----------authenticate()-----------
Authenticate : true
----------getScoreSheet()-----------
Done. 2-dimensional array initialized each value in the array to 100.00
----------writeList()-----------
Data has been saved in file
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.