Chapter 30, Problem 30.1PE

Program Plan Intro

Assign grades

Program Plan:

• Import necessary packages into program.
• Define the class named “Exercise30_01”.
  • Define main method.
  • Define the “Scanner” object “obj” for input.
  • Prompt the user and get the number of students “N” from user.
  • Declare the array variable “marks[]” in type of “double”.
  • Prompt and get scores using “for” loop.
  • Using “DoubleStream” class assign maximum value into “best” variable.
  • Declare the “grade” in type of “character”.
  • Using “for” loop which is execute from “0” to “marks.length”.
    • Using “if..elseif..else” condition, check the score value.
      • If the value greater than “best-10”, assign “A” to “grade”.
      • If the value greater than “best-20”, assign “B” to “grade”.
      • If the value greater than “best-30”, assign “C” to “grade”.
      • If the value greater than “best-40”, assign “D” to “grade”.
      • Otherwise, assign “E” to “grade”.
      • Print appropriate grade with statement on screen.

Program Description Answer

The following JAVA code is to calculate the grade of student scores using “DoubleStream”.

Explanation of Solution

Program:

/*Include necessary packages*/

import java.util.Scanner;

//Include Stream package

import java.util.stream.DoubleStream;

//Class definition

class Exercise30_01

{

//Main method

public static void main(String[] args)

{

/*Definition of "Scanner" object*/

Scanner obj = new Scanner(System.in);

/*Prompt the user for number of students*/

System.out.print("Enter number of students: ");

//Get input from user

int N = obj.nextInt();

/*Declaration and definition of array variable*/

double[] marks = new double[N];

//Prompt the user for marks

System.out.print("Enter " + N + " scores: ");

//Loop

for (int i = 0; i < marks.length; i++)

{

/*Get scores and store into "marks[]" variable*/

marks[i] = obj.nextDouble();

}

/*Get maximum value using stream*/

double best = DoubleStream.of(marks).max().getAsDouble();

//Declaration of variable

char grade;

//Loop

for (int i = 0; i < marks.length; i++)

{

/*Condition to check marks*/

if (marks[i] >= best - 10)

//Assign grade

grade = 'A';

/*Condition to check marks*/

else if (marks[i] >= best - 20)

//Assign grade

grade = 'B';

/*Condition to check marks*/

else if (marks[i] >= best - 30)

//Assign grade

grade = 'C';

/*Condition to check marks*/

else if (marks[i] >= best - 40)

//Assign grade

grade = 'D';

//Else statement

else

//Assign grade

grade = 'F';

//Print statement

System.out.println("Student " + i + " score is " +marks[i] + " and grade is " + grade);

}

}

}

Sample Output

Enter number of students: 4

Enter 4 scores: 40 55 70 58

Student 0 score is 40.0 and grade is C

Student 1 score is 55.0 and grade is B

Student 2 score is 70.0 and grade is A

Student 3 score is 58.0 and grade is B