Question

/*      Problem 1
*       Write and run a java program that prints out two things you have learned
*   so far in this class, and three things you hope to learn, all in different lines. 
*/

You could write any two basic  things in Java.
/*      Problem 2
*       The formula for finding the area of a triangle is 1/2 (Base * height). 
*       The formula for finding the perimeter of a rectangle is 2(length * width). 
*   Write a program that prompts the user to enter the base and height of a triangle. 
*       The program then calculates the area of the triangle.
*       The program also prompts the user to enter the length and width of a rectangle.
*   The program then calculates the perimeter of the rectangle. 
*       Your code must print out: the base of the triangle, the width of the triangle, the area
*       of the triangle, the length of the rectangle, the width of the rectangle, and the area of the rectangle.
*       (5 Points.)
*/

/*      Problem 3
*       Write and run a java program that prompts you to enter your year of birth. 
*       The program then returns your age by subtracting your year of birth from the
*   current year. The program must print: You are x years old, where x is your 
*       age. You must import the scanner class (5 Points.)

/*      Problem 4
*       Write a java program that asks the user to enter her\his first name,
*       middle initial, last name, class name, letter grade, and GPA.
*       The program then prints out the above items as follows.
*       Line 1: Your name is first name, middle initial, last name.
*       Line 2: You are enrolled in class name
*       Line 3: You scored letter grade ... in class name
*       Line 4: Your GPA in class name is GPA

*       Hint: To read characters from the scanner, you should use this syntax:
*       String firstName = input.nextLine();

*       Note that you will use both String and double variable types.

* Note that we use Notepad ++ in our class for java and we also use cmd

Answer 1

Problem1:

//Program to be saved as Problem1.java
import java.util.*;
public class Problem1 {

   public static void main(String[] args) {
      
       Scanner input=new Scanner(System.in);
       String thingslearned1,thingslearned2;
       String thingstobelearned1,thingstobelearned2,thingstobelearned3;
      
       //read the things you have learnt so far
       System.out.println("\nEnter two things you have learned so far in this class: ");
       thingslearned1=input.nextLine();
       thingslearned2=input.nextLine();
      
       //read the things you hope to learn
       System.out.println("\nEnter three things you hope to learn: ");
       thingstobelearned1=input.nextLine();
       thingstobelearned2=input.nextLine();
       thingstobelearned3=input.nextLine();
      
       //print out the things each in a separate line using println
       System.out.println("\nThe two things you have learned so far in this class: ");
       System.out.println(thingslearned1);
       System.out.println(thingslearned2);
       System.out.println("\nThe three things you hope to learn: ");
       System.out.println(thingstobelearned1);
       System.out.println(thingstobelearned2);
       System.out.println(thingstobelearned3);
   }

}

Output:

Problem2:

//Program to be saved as Problem2.java
import java.util.*;
public class Problem2 {

   public static void main(String[] args) {
      
       double baseOfTriangle,heightOfTriangle;
       double lengthOfRectangle,widthOfRectangle;
       double areaOfTriangle,perimeterOfRectangle;
      
       Scanner input=new Scanner(System.in);
      
       //read the base of the triangle
       System.out.print("\nEnter the base of the triangle: ");
       baseOfTriangle=input.nextDouble();
      
       //read the height of the triangle
       System.out.print("\nEnter the height of the triangle: ");
       heightOfTriangle=input.nextDouble();
      
       //read the length of the rectangle
       System.out.print("\nEnter the length of the rectangle: ");
       lengthOfRectangle=input.nextDouble();
      
       //read the width of the rectangle
       System.out.print("\nEnter the width of the rectangle: ");
       widthOfRectangle=input.nextDouble();
      
       //calculate the area of the triangle
       areaOfTriangle = (1.0/2.0)*(baseOfTriangle*heightOfTriangle);
      
       //calculate the perimeter of the rectangle
       perimeterOfRectangle = 2*lengthOfRectangle*widthOfRectangle;
      
       //print the results
       System.out.println("\nThe base of the triangle is: "+baseOfTriangle);
       System.out.println("\nThe height of the triangle is: "+heightOfTriangle);
       System.out.println("\nThe area of the triangle is: "+areaOfTriangle);
       System.out.println("\n\nThe length of the rectangle is: "+lengthOfRectangle);
       System.out.println("\nThe width of the rectangle is: "+widthOfRectangle);
       System.out.println("\nThe perimeter of the rectangle is: "+perimeterOfRectangle);
      
      
   }

}

Output:

Problem3:

//Program to be saved as Problem3.java
import java.util.*;
public class Problem3 {

   public static void main(String[] args) {
       Scanner input=new Scanner(System.in);
      
       int yearOfBirth, age;
      
       //read the year of birth
       System.out.print("\nEnter your year of birth: ");
       yearOfBirth=input.nextInt();

       //create a Calender object and get the current calender date
       Calendar calendar = Calendar.getInstance();
       //calculate age, get the current year using calender object
       age= calendar.get(calendar.YEAR) - yearOfBirth;
      
       //print the output
       System.out.println("\nYou are "+age+" years old.");  
   }

}

Output:

Problem4:

//Program to be saved as Problem3.java
import java.util.*;
public class Problem4 {

   public static void main(String[] args) {
       Scanner input=new Scanner(System.in);
      
       String firstname, middlename, lastname, classname, lettergrade;
       double GPA;

       //asks the user to enter his first name,middle initial, last name, class name, letter grade, and GPA.
       System.out.print("\nEnter firstname: ");
       firstname=input.nextLine();
       //asks the user to enter his middle initial
       System.out.print("\nEnter middlename: ");
       middlename=input.nextLine();
       //asks the user to enter his last name
       System.out.print("\nEnter lastname: ");
       lastname=input.nextLine();
       //asks the user to enter his class name
       System.out.print("\nEnter class name: ");
       classname=input.nextLine();
       //asks the user to enter his letter grade
       System.out.print("\nEnter letter grade: ");
       lettergrade=input.nextLine();
       //asks the user to enter his GPA
       System.out.print("\nEnter GPA: ");
       GPA=input.nextDouble();
      
       //print the details entered
       System.out.println("\nYour name is "+firstname+", "+middlename+", "+lastname);
       System.out.println("You are enrolled in "+classname);
       System.out.println("You scored letter grade "+lettergrade+" in "+classname);
       System.out.println("Your GPA in "+classname+" is "+GPA);
      
   }

}

Output: