Question

I should use the array and loop to create a java program according to the instruction, but I have no idea how to do it.
Introduction This lab assignment continues to give you practice using loops, particularly loops with variable termination conditions, and it also provides you an opportunity to use one-dimensional arrays. Recall that an array is used to store a collection of data. The data can be values of Java primitive data types or else objects (for instance, String objects), but the data stored must all be of the same type. An array is created in Java using a statement of the form BaseType[] arrayName = new BaseType [length]; where Base Type is the underlying type of data stored in the array, arrayName is just a variable name used to refer to the array, and length is a positive integer indicating the number of elements in the array. An array element can be referred to using arrayName[i], where i is an integer index (starting with 0). The length of the array is stored in the variable arrayName.length. The arrays used in this assignment will all be one-dimensional (that is, they won't be arrays of arrays), and they will all use Java primitive data types as the base type. For the assignment, you are to create a program using two arrays of type double to store multiple values for x and y, where y is defined as the below function. y = 20.0 * \sin x| It is assumed that the angles for the sine function are measured in radians. In the program, both the values for x and y are computed based on input from the user. Once the values are found, the program should print them out as indicated by the examples. The program should also print out a graphical representation of the function, using a sequence of '*'s to indicate the magnitude of y. Lab Objectives By the end of the lab, you should be able to: • create nested loops and loops with variable termination conditions; create and manipulate one-dimensional arrays.

Answer 1

Scanner class is used to get input from the user (from keyboard).

PROGRAM:

PlotSine.java :

package HomeworkLib.answers;

import java.util.Scanner;

public class PlotSine {
    public static void main(String[] args) {
        double[] x,y;
        Scanner sc = new Scanner(System.in);

        // asking user to input the length of array x
        System.out.print("Please enter the number of x values to process: ");
        // getting value from user
        int n = sc.nextInt();
        //checking if length is <= zero, if true then printing error msg and exiting
        if(n <= 0){
            System.out.println("The number of x values must be an integer greater than 0.");
            // exiting the program if condition is true with exit status as 1
            System.exit(1);
        }

        // this portion will be executed only if the above condition is false
        System.out.print("Enter a minimum value for x: ");
        // getting the starting value of x
        double min_val = sc.nextDouble();

        System.out.print("Enter the amount to increment x: ");
        //getting the increment value
        double inc = sc.nextDouble();
        //checking if increment value is <= zero, if true then printing error msg and exiting
        if(inc <= 0){
            System.out.println("The increment must be a decimal number greater than 0.");
            System.exit(1);
        }

        // this portion will be executed only if the above condition is false
        // creating two arrays of double type with length entered by user
        x = new double[n];
        y = new double[n];

        // initializing the 1st element of both the arrays
        x[0] = min_val;
        y[0] = 20.0 * Math.abs(Math.sin(x[0]));

        // calculating the angles and storing them in array y and also printing the values to the screen
        // It is done in the same loop in order to reduce the computation time of the program
        System.out.println("\nValues");

        // printf takes a formatted string
        // ".3f": 'f' signifies that it will be replaced by a double,
        // '.3' signifies that number of digits will be three after the decimal point
        System.out.printf("x: %.3f, y: %.3f\n",x[0], y[0]);

        // 1st for loop
        for(int i = 1; i < n; i++){
            // incrementing the value of array x by user input
            x[i] = x[i-1] + inc;
            // calculating the angle and storing in array y
            y[i] = 20.0 * Math.abs(Math.sin(x[i]));
            // printing the output to the screen
            System.out.printf("x: %.3f, y: %.3f\n",x[i], y[i]);
        }

        // printing the graph
        System.out.println("\nGraph");
        //2nd for loop
        // outer for loop will loop through the entire array y
        for (int i = 0; i < n ; i++) {
            // printing ":" without changing line
            System.out.print(":");
            //inner for loop will execute the whole-number part of array-y times
            // whole-number part is calculated by taking the floor of the floating point number
            for (int j = 0; j < Math.floor(y[i]); j++) {
                // printing "*" without changing line
                System.out.print("*");
            }
            // printing a new line
            System.out.println();
        }
    }
}

OUTPUT:

case 1:

Please enter the number of x values to process: 10
Enter a minimum value for x: 0
Enter the amount to increment x: 0.25

Values
x: 0.000, y: 0.000
x: 0.250, y: 4.948
x: 0.500, y: 9.589
x: 0.750, y: 13.633
x: 1.000, y: 16.829
x: 1.250, y: 18.980
x: 1.500, y: 19.950
x: 1.750, y: 19.680
x: 2.000, y: 18.186
x: 2.250, y: 15.561

Graph
:
:****
:*********
:*************
:****************
:******************
:*******************
:*******************
:******************
:***************

case 2:

Please enter the number of x values to process: 9
Enter a minimum value for x: -1.5707963267
Enter the amount to increment x: 0.78539816339

Values
x: -1.571, y: 20.000
x: -0.785, y: 14.142
x: 0.000, y: 0.000
x: 0.785, y: 14.142
x: 1.571, y: 20.000
x: 2.356, y: 14.142
x: 3.142, y: 0.000
x: 3.927, y: 14.142
x: 4.712, y: 20.000

Graph
:********************
:**************
:
:**************
:********************
:**************
:
:**************
:********************

case 3:

Please enter the number of x values to process: 10
Enter a minimum value for x: -5
Enter the amount to increment x: 0.20

Values
x: -5.000, y: 19.178
x: -4.800, y: 19.923
x: -4.600, y: 19.874
x: -4.400, y: 19.032
x: -4.200, y: 17.432
x: -4.000, y: 15.136
x: -3.800, y: 12.237
x: -3.600, y: 8.850
x: -3.400, y: 5.111
x: -3.200, y: 1.167

Graph
:*******************
:*******************
:*******************
:*******************
:*****************
:***************
:************
:********
:*****
:*

case 4:

Please enter the number of x values to process: 0
The number of x values must be an integer greater than 0.

case 5:

Please enter the number of x values to process: 100
Enter a minimum value for x: -50
Enter the amount to increment x: 0
The increment must be a decimal number greater than 0.

SCREENSHOTS:

PlotSine.java:

PlotSine.java package HomeworkLib.answers; import java.util.Scanner; public class PlotSine { public static void main(String[] args) { double[] x,y; Scanner sc = new Scanner(System.in); // asking user to input the length of array x System.out.print("Please enter the number of x values to process: "); // getting value from user int n = sc.nextInt(); //checking if length is <= zero, if true then printing error msg and exiting if(n <= 0) { System.out.println("The number of x values must be an integer greater than 0."); // exiting the program if condition is true with exit status as 1 System.exit( status: 1); // this portion will be executed only if the above condition is false System.out.print("Enter a minimum value for x: "); // getting the starting value of x double min_val = sc.nextDouble(); System.out.print("Enter the amount to increment x: "); //getting the increment value double inc = sc.nextDouble(); //checking if increment value is <= zero, if true then printing error msg and exiting if(inc <= 0){ System.out.println("The increment must be a decimal number greater than 0."); System.exit( status: 1);

PlotSine.java System.out.println("the increment must be a decrILIAI number greater than 0.77 System.exit( status: 1); 0 00 Jin WH // this portion will be executed only if the above condition is false // creating two arrays of double type vith length entered by user X = new double[n]; y = new double[n]; // initializing the 1st element of both the arrays x[0] = min_val; Y[0] = 20.0 * Math.abs(Math.sin(x[0])); in iis // calculating the angles and storing them in array y and also printing the values to the screen // It is done in the same loop in order to reduce the computation time of the program System.out.println("\nValues"); N ODOO // printf takes a formatted string // ".3f": 'f' signifies that it will be replaced by a double, // 1.3' signifies that number of digits will be three after the decimal point System.out.printf("x: 8.3f, y: 8.3f\n",[0], Y[0]); D D // 1st for loop for(int i = 1; i<n; i++) { // incrementing the value of array x by user input x[i] = x[i-1] + inc; // calculating the angle and storing in array y v[i] = 20.0 * Math.abs(Math.sin(x[i])); // printing the output to the screen System.out.printf("x: 8.3f, y: 8.3f\n",x[i], v[i]); D D A NO 00 // printing the graph System.out.println("\nGraph"); PlotSine > main

c PlotSine.java ISL TOT 100 for(int i = 1; i<n; i++) { // incrementing the value of array x by user input x[i] = x[i-1] + inc; // calculating the angle and storing in array y y[i] = 20.0 * Math.abs(Math.sin(x[i])); // printing the output to the screen System.out.printf("x: 8.3f, y: 8.3f\n", x[i], v[i]); // printing the graph System.out.println("\nGraph"); //2nd for loop // outer for loop vill loop through the entire array y for (int i = 0; i<n; i++) { // printing ":" without changing line System.out.print(":"); //inner for loop vill execute the whole-number part of array-y times // whole-number part is calculated by taking the floor of the floating point number for (int i = 0; i < Math.floor(v[i]); j++) { // printing "A" without changing line System.out.print("*"); // printing a new line System.out.println();

Outputs:

case 1:

Run: PlotSinex "C:\Program Files\Java\jdk1.8.0 144\bin\java.exe" ... Please enter the number of x values to process: 10 Enter a minimum value for x: 0 Enter the amount to increment x: 0.25 AO. * → IV Values x: 0.000, y: 0.000 X: 0.250, y: 4.948 x: 0.500, y: 9.589 x: 0.750, y: 13.633 x: 1.000, y: 16.829 x: 1.250, y: 18.980 x: 1.500, y: 19.950 x: 1.750, y: 19.680 x: 2.000, y: 18.186 x: 2.250, y: 15.561 Graph ******* ************ *************** ************** ************ ***************** Process finished with exit code 0

case 2:

Run: PlotSinex "C:\Program Files\Java\jdk1.8.0 144\bin\java.exe" ... Please enter the number of x values to process: 9 Enter a minimum value for x: -1.5707963267 Enter the amount to increment x: 0.78539816339 → IR 70 Values x: -1.571, y: 20.000 x: -0.785, y: 14.142 x: 0.000, y: 0.000 x: 0.785, y: 14.142 x: 1.571, y: 20.000 x: 2.356, y: 14.142 x: 3.142, y: 0.000 x: 3.927, y: 14.142 x: 4.712, y: 20.000 Graph ******* ********** ************** ********* ** **************** ************* ********* Process finished with exit code 0

case 3:

Run: + → If PlotSinex "C:\Program Files\Java\jdk1.8.0_144\bin\java.exe" ... Please enter the number of x values to process: 10 Enter a minimum value for x: -5 Enter the amount to increment x: 0.20 bu Values x: -5.000, y: 19.178 x: -4.800, y: 19.923 x: -4.600, y: 19.874 x: -4.400, y: 19.032 x: -4.200, y: 17.432 x: -4.000, y: 15.136 x: -3.800, y: 12.237 x: -3.600, y: 8.850 x: -3.400, y: 5.111 x: -3.200, y: 1.167 Graph ****************** *************** ** ** ************* ****************** *************** *************** ************ **** Process finished with exit code 0

case 4:

Run: PK PlotSine "C:\Program Files\Java\jdk1.8.0_144\bin\java.exe" ... Please enter the number of x values to process: 0 The number of x values must be an integer greater than 0. → If: 71 Process finished with exit code 1

case 5:

Run: PlotSinex "C:\Program Files\Java\jdk1.8.0_144\bin\java.exe" ... Please enter the number of x values to process: 100 Enter a minimum value for x: -50 Enter the amount to increment x: 0 The increment must be a decimal number greater than 0. → If IV Process finished with exit code 1

REMOVE "PACKAGE CHEGG.ANSWERS;" LINE BEFORE EXECUTING!

HOPE THIS HELPS!