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NetBeans cannot perform IO operation

The NetBeans IDE keeps putting the error, saying that it cannot find the symbol IO. Cannot do any input or output operations with IO is since "IO" is considered as a symbol. Cannot find out why this is so.
Here is the very simple program i tried to run :-
public class CourseGrade
{
public static void main(String[] args)
{
int examWeight = 70; // Percentage weight given to examination
int labWeight = 20; // Percentage weight given to lab work
int hwWeight = 10; // Percentage weight given to homework
assignment
double examScore; // Examination score obtained by student
double labScore; // Lab score obtained by student
double hwScore; // Homework score obtained by student
double finalGrade; // Final grade obtained by student
// Ask student to input scores for exam, lab and nomework
IO.output("Enter your exam grade: ");
examScore = IO.inputDouble( );
IO.output("Enter your lab grade: ");
labScore = IO.inputDouble( );
IO.output("Enter your homework grade: ");
hwScore = IO.inputDouble( );
// Computer final grade as the weighted sum of exam, lab and
homework scores
examScore = examScore * (examWeight / 100.0);
labScore = labScore * (labWeight / 100.0);
hwScore = hwScore * (hwWeight / 100.0);
finalGrade = examScore + labScore + hwScore;
// Output the final grade
IO.outputln("Your final grade is " + finalGrade);
}
}
This is the Error that i got:-
error: cannot find symbol
IO.output("Enter the exam score :- \n");
symbol: variable IO
location: class CourseGrade
I got this output for each of the IO that i used.
What is causing this ?

Display bill total, Java public void display() error

I'm having some trouble executing the total bill display. I asked my professor who gave me this small block of code, which I modified to meet my needs, but for some reason it is not executing and has the error:
Illegal start to expression for line --> public void display().
The compiler also suggests to end with a semi colon which I don't believe is accurate.
What am I missing that public void display() is not being executed and is erroneous?
import java.util.Scanner;
public class CoffeeShop
{
/* Author:
Date:
Program: Create a Coffee Shop application that uses a while loop to build a customer order. The Coffee Shops sells coffee ($3.25), espresso ($4.25), and tea ($2.75). The coffee selection presents the customer with the choices of iced (no charge), cream (50 cents), and sugar (50 cents). The espresso selection presents the customer with choice of caramel (no charge) and chocolate (no charge) with one shot (no charge) or two shots ($1.25) of espresso. Once the customer is done, he or she will receive a bill of the total price. After each selection, the customer will have the choice of returning to the main menu for additional purchases. Use nested loops to handle customers' submenu selections.
*/
public static void main(String[] args)
{
//declarations
double coff = 3.25;
double esp = 4.25;
double tea = 2.75;
double cream = .50;
double sugar = .50;
double dblShot = 1.25;
int dblshotQty = 0;
int userInput = 0;
int userInput2 = 0;
int coffQty = 0;
int espQty = 0;
int teaQty = 0;
int creamQty = 0;
int sugarQty = 0;
double runTotal = 0;
double totalCoff = 0;
double totalEsp = 0;
double totalTea = 0;
double totalBill = 0;
Scanner scan = new Scanner(System.in);
System.out.print("Would you like to place an order? press 1 for yes or 2 for no :");
//start a loop with a control variable asking if they would like a cup of coffee yes or no
userInput = scan.nextInt();
while(userInput == 1)
{
System.out.print("Enter 1 for Coffee, 2 for Espresso, or 3 for tea: ");
userInput2 = scan.nextInt();
switch(userInput2)
//if 1 is pressed coffee is ordered
{ // open switch
case '1':
{
coffQty = coffQty + 1;
System.out.print("Press 1 if you would like your coffee iced or 2 for no: ");
userInput = scan.nextInt();
}
{
System.out.print("Press 1 if you would like cream for $.50 or 2 for no: ");
userInput = scan.nextInt();
if ( userInput == 1 )
{
creamQty = creamQty + 1;
}
}
{
System.out.print("Press 1 if you would like sugar for $.50 or 2 for no: ");
userInput = scan.nextInt();
if ( userInput == 1 )
{
sugarQty = sugarQty + 1;
}
}//end case 1
break;
// espresso is ordered ask for double shot
case '2':
{
espQty = espQty +1;
System.out.println("Press 1 for a double shot for $1.25 or 2 for no: ");
userInput = scan.nextInt();
if(userInput == 1)
{
dblshotQty = dblshotQty +1;
}
}//end case 2
break;
//tea is ordered
case '3':
{
teaQty = teaQty + 1;
System.out.println("You have selected tea! Great Choice.");
}//end case 3
}//end switch
// create output display for total bill adding all totals
public void display()
{
double totalCoff = coffQty * coff + cream * creamQty + sugar * sugarQty;
double totalEsp = espQty * esp + dblshot * dblshotQty;
double totalTea = teaQty * tea;
System.out.println("Order: \n "+coffQty + " Coffee"
+ "\n "+creamQty +" Cream"
+ "\n "+sugarQty + " Sugar"
+ "\nTotal Coffee: "+ totalCoff);
System.out.println(" "+teaQty + " Tea"
+ "\nTotal Tea: "+ totalTea);
System.out.println(" "+espQty + " Espresso"
+ "\n "+dblshotQty +" Double shot"
+ "\nTotal Espresso: "+ totalEsp);
double totalBill = totalCoff+totalEsp+totalTea;
System.out.println("\nTotal drink order: "+totalBill);
}
break;
} // end while
}
} // end of class

Your code structure is making things difficult for you. As mentioned by #Carcigenicate, (nice name btw), you have you declared a method inside the main method. Once you change that, you'll notice now that now the display method shows compiler errors. This is because the variables referenced in display are no longer visible. You have a few options:
Rethink the design of the class i.e What methods should exist and how they will be called.
Take the display method outside the main method and then make the variables member variables that are visible to the methods you need. Read about the effects of using member variables first.
Remove the display method completely and move the logic to the main method.

I see a few main problems:
You defined display inside of main, inside of a while loop. You can't define methods inside of methods, let alone inside of loops. Move display outside of main, but still inside the class.
You have a misplaced break floating around under display. Get rid of that, as that will also be an error.
As #MiiinimalLogic pointed out, you're relying on data from main inside of display. You'll need to pass the data from main to display as arguments.

Java Program Loop

i want to be able to have the program to start over (show the enter loan amount prompt) after typing 'y' when asked "to calculate the program again" or end program if user input 'n'.
import java.util.Scanner;
public class MonthlyMortgageRate {
public static void main(String[] args) {
double Amount;
double Rate;
double Months;
double outputNum1;
Scanner in = new Scanner(System.in);
System.out.print("Enter loan amount:");
Amount = in.nextDouble();
System.out.print("Enter rate:");
Rate = in.nextDouble() / 100 / 12;
System.out.print("Enter year:");
Months = in.nextDouble() * 12;
outputNum1 = Rate * Amount / (1 - Math.pow(1 + Rate, -Months));
if (Amount <= 0)
System.out.println("You must enter positive numeric data!");
else
System.out.printf("Monthly payment is: $ %.2f%n", outputNum1);
System.out.println("would you like to calculate again?(y/n)");
}
private static double inputNum2(double d) {
throw new UnsupportedOperationException("Not supported yet.");
}
}

Basically you need to loop the code in main.
do {
// your code here
System.out.println("would you like to calculate again?(y/n)");
} while (in.next().equalsIgnoreCase("y"))

Add the following to your code:
Boolean doagain = true;
// after Scanner in
while(doagain)
{
// your code
System.out.println("would you like to calculate again?(y/n)");
if ( in.next().toLowerCase().equals("n") ) doagain = false;
} // end while
// your code
Enjoy Cliff

my program doesn't run completely [closed]

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Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
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For some reason, my program stops when it reaches the part that asks the user if it know it's exam 1 score. I need the user to be able to enter yes or no. Why does the program stop? I need it to work properly. I have all the if-else statements. I am able to enter the percentage weights, but that is all that the program will do. More must be done. My code extends far beyond entering the percentage weights. Please help me.
import java.util.Scanner;
public class GradeCalculation {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner grade = new Scanner (System.in);
// A new scanner must be created. The scanner is essential to this program performing properly.
double A = 90-100;
double B = 80-89;
double C = 70-79;
double D = 60-69;
double F = 0-59;
String LetterGrade;
String yes;
String no;
double Exam1, Exam2, finalExam, Labs, Projects, Attendance, Quizzes;
double Exam1Grade, Exam2Grade, finalExamGrade, LabAverage, ProjectsAverage, AttendanceAverage, QuizzesAverage;
double knownWeight;
double PercentageWeights;
// As always, the variables must be declared at the beginning of the program.
System.out.print(
"Grading Scale:\n"+
"A = 90-100 \n"+
"B = 80-89 \n"+
"C = 70-79 \n"+
"D = 60-69 \n"+
"F = 00-59 \n");
System.out.println("What letter grade do you want to achieve in this course?");
LetterGrade = grade.next();
// The user will type the letter grade that it wants in this part.
System.out.println("\nEnter Percentage Weights: \t");
String input = grade.nextLine();
// The string above is needed when the user enters the exam grades and averages.
System.out.print("\n\nExam 1: \t");
Exam1 = grade.nextShort();
System.out.print("\nExam 2: \t");
Exam2 = grade.nextShort();
System.out.print("\nFinal Exam: \t");
finalExam = grade.nextShort();
System.out.print("\nLabs: \t");
Labs = grade.nextShort();
System.out.print("\nProjects: \t");
Projects = grade.nextShort();
System.out.print("\nAttendance: \t");
Attendance = grade.nextShort();
System.out.print("\nQuizzes: \t");
Quizzes = grade.nextShort();
PercentageWeights = (int)(Exam1 + Exam2 + finalExam + Labs + Projects + Attendance + Quizzes);
// The equation above will provide the sum of the percentage weights. Since the variables in the equation were
// originally declared as doubles, I had to put "int" before the actual equation.
if (PercentageWeights > 100 || PercentageWeights < 100) {
System.out.println("\nWeights do not add up to 100. Program exiting. Have a nice day!");
System.exit(0);
}
else {
System.out.println("\nEnter your scores out of a 100: \t");
}
// The part above is very important to continue the rest of the program. If the sum of the percentage weights equals 100,
// the program will continue to run. If the sum is greater than or less than 100, the program will terminate.
System.out.print("\nDo you know your Exam 1 score?");
if (input.equalsIgnoreCase("yes")) {
System.out.print("\nScore received on Exam 1: ");
Exam1Grade = grade.nextDouble();
}
else{
Exam1Grade = 0;
}
System.out.print("\nDo you know your Exam 2 score?");
if (input.equalsIgnoreCase("yes")) {
System.out.print("\nScore received on Exam 2: ");
Exam2Grade = grade.nextDouble();
}
else{
Exam2Grade = 0;
}
System.out.print("\nDo you know your final exam score?");
if (input.equalsIgnoreCase("yes")){
System.out.print("\nScore received on final exam: ");
finalExamGrade = grade.nextDouble();
}
else{
finalExamGrade = 0;
}
System.out.print("\nDo you know your lab average?");
if (input.equalsIgnoreCase("yes")){
System.out.print("\nAverage lab grade: ");
LabAverage = grade.nextDouble();
}
else{
LabAverage = 0;
}
System.out.print("\nDo you know your project average?");
if (input.equalsIgnoreCase("yes")){
System.out.print("\nAverage project grade: ");
ProjectsAverage = grade.nextDouble();
}
else{
ProjectsAverage = 0;
}
System.out.print("\nDo you know your quiz average?");
if (input.equalsIgnoreCase("yes")) {
System.out.print("\nAverage quiz grade: ");
QuizzesAverage = grade.nextDouble();
}
else{
QuizzesAverage = 0;
}
System.out.print("\nDo you know your attendance average?");
if (input.equalsIgnoreCase("yes")){
System.out.print("\nAverage Attendance Grade: ");
AttendanceAverage = grade.nextDouble();
}
else{
AttendanceAverage = 0;
}
// The user has finished answering the questions. Now the program will automatically calculate the data based on
// what the user typed into the program.
double CurrentGrade, avgToFinalLetterGrade, WeightandGrade, finalOverallGrade;
// The doubles above need to be declared in order for the equations below to work properly.
WeightandGrade = (int)((Exam1 * Exam1Grade) + (Exam2 * Exam2Grade) + (finalExam * finalExamGrade) + (Labs * LabAverage) + (Projects * ProjectsAverage) + (Quizzes * QuizzesAverage) + (Attendance * AttendanceAverage));
CurrentGrade = (int)((WeightandGrade) / (Exam1 + Exam2 + finalExam + Labs + Projects + Quizzes + Attendance ));
knownWeight = (Exam1 + Exam2 + finalExam + Labs + Projects + Quizzes + Attendance);
if (grade.equals(A)){
finalOverallGrade = 90;
}
else if (grade.equals(B)){
finalOverallGrade = 80;
}
else if (grade.equals(C)){
finalOverallGrade = 70;
}
else if (grade.equals(D)){
finalOverallGrade = 60;
}
else
finalOverallGrade = F;
avgToFinalLetterGrade = (((100-finalOverallGrade) * (WeightandGrade)) / (100 - knownWeight));
// The equations above are one of the last parts of the program. These equations are critical to determine whether or not the user received its desired letter grade.
// If the desired grade was not reached, the program will give a score that the user must consistently receive in order to possibly reach the desired letter grade.
if (finalOverallGrade >= 90){
System.out.print("Congratulations! You got an A in the class! Hooray!");
}
else if (finalOverallGrade >=80 && finalOverallGrade < 90){
System.out.print("Good job. You got a B in the class!");
}
else if (finalOverallGrade >=70 && finalOverallGrade < 80){
System.out.print("You got a C in the class.");
}
else if (finalOverallGrade >=60 && finalOverallGrade < 70){
System.out.print("You got a D in the class.");
}
else
System.out.print("I'm sorry, but you have a failing grade in the class. May your GPA have mercy on your soul.");
}
}

There are quite a lot of things wrong with this code.
Doing double A=90-100; will set A equal to -10;
However, for your current question:
You do String input = grade.nextLine();
You never change input, and so if input isn't "yes", it will just skip getting the grades for each piece.
(You might want to also consult Using scanner.nextLine() for other pitfalls with using scanner.nextLine() intermixed with scanner.nextInt or similar [in summary: if you do scanner.nextInt, this doesn't consume the newline, so scanner.nextLine() will just get that newline and not the next line after that you might be expecting to get])

input = grade.nextLine() reads the remainder of the line with the user's "percentage weights" input on it. So unless the user had a priori knowledge to enter "yes", input will be empty.
I.e., you need to update input with user input before if (input.equalsIgnoreCase("yes")) {....

Java loan calculator

I'm trying to code a loan calculator. I seem to be having issues. I am trying to get an input from the user and validate the input. I know I am doing it wrong the problem is I'm scratching my head wondering how to do it right.
I get a red line on the d = getDouble(sc, prompt); and the i = getInt(sc, prompt); which I understand I don't have that coded correctly. I'm just unsure how to go about fixing it.
I also have to validate the continue statement which I wasn't to sure the best way to go about that and finally the instructor expects the code to be 80 lines or less which I am right about 80 lines. I guess I'm looking for a better way to do this but being new I'm scratching my head and I'm hoping someone can lend a hand.
As always I really appreciate the help.
import java.util.Scanner;
import java.text.NumberFormat;
public class LoanCalculator
{
public static double getDoubleWithinRange(Scanner sc, String prompt, double min, double max)
{
double d = 0.0;
boolean isValid = false;
while(isValid == false);
{
d = getDouble(sc, prompt);
if (d <= min)
{
System.out.println("Error! Number must be greater tha 0.0");
}
else if (d >= max)
{
System.out.println("Error number must be less than 1000000.0");
}
else
isValid = true;
}
return d;
}
public static int getIntWithinRange(Scanner sc, String prompt, int min, int max)
{
int i = 0;
boolean isvalid = false;
while(isvalid == false)
{
i = getInt(sc, prompt);
if (i <= min)
System.out.println("Error! Number must be more than 0");
else if (i >= max)
System.out.println("Error! Number must be less than 100");
else
isvalid = true;
}
}
public static void main(String[] args)
{
System.out.println("Welcome to the loan calculator");
Scanner sc = new Scanner(System.in);
String choice = "y";
while (choice.equalsIgnoreCase("y"))
{
System.out.println("DATA ENTRY");
double loanAmount = getDoubleWithinRange(sc, "Enter loan amount: ", 0.0, 1000000.0);
double interestRate = getDoubleWithinRange(sc, "Enter yearly interest rate: ", 0, 20);
int years = getIntWithinRange(sc, "Enter number of years: ", 0, 100);
int months = years * 12;
double monthlyPayment = loanAmount * interestRate/
(1 - 1/Math.pow(1 + interestRate, months));
NumberFormat currency = NumberFormat.getCurrencyInstance();
NumberFormat percent = NumberFormat.getPercentInstance();
percent.setMaximumFractionDigits(3);
System.out.println("RESULST");
System.out.println("Loan Amount" + currency.format(loanAmount));
System.out.println("Yearly interest rate: " + percent.format(interestRate));
System.out.println("Number of years: " + years);
System.out.println("Monthly payment: " + currency.format(monthlyPayment));
System.out.println();
System.out.println("Continue? (y/n): ");
choice =sc.next();
System.out.println();
}
}
}

You haven't made the implementation of your getDouble(Scanner,String) and getInt(Scanner,String) that's why you're getting the red line.
since you already have a scanner, and prompt string change it to this
System.out.print(prompt);
d = sc.nextDouble();
and for the integer
System.out.print(prompt);
i = sc.nextInt();

I think getDouble and getInt are string functions so you would have to get a string first then call those methods. However, since you have a scanner, I assume you want to use that with the nextXXX methods:
Scanner sc = new Scanner (System.in);
double d = sc.nextDouble();
You can use this complete snippet for educational purposes:
import java.util.Scanner;
class Test {
public static void main (String args[]) {
Scanner sc = new Scanner (System.in);
System.out.print("Enter your double: ");
double d = sc.nextDouble();
System.out.print("Enter your integer: ");
int i = sc.nextInt();
System.out.println("You entered: " + d + " and " + i);
}
}
Transcript:
Enter your double: 3.14159
Enter your integer: 42
You entered: 3.14159 and 42
Basically, the process is:
Instantiate a scanner, using the standard input stream.
Use print for your prompts.
Use the scanner nextXXX methods for getting the input values.
A little more assistance here, based on your comments.
In your main function, you have:
double loanAmount = getDoubleWithinRange(sc, "Enter loan amount: ", 0.0, 1000000.0)
and that function has the prototype:
public static double getDoubleWithinRange(
Scanner sc, String prompt, double min, double max)
That means those variables in the prototype will be set to the values from the call. So, to prompt for the information, you could use something like (and this is to replace the d = getDouble(sc, prompt); line):
System.out.print(prompt);
double d = sc.nextDouble();
And there you have it, you've prompted the user and input the double from them. The first line prints out the prompt, the second uses the scanner to get the input from the user.
As an aside, your checks for the minimum and maximum are good but your error messages have hard-coded values of 0 and 100K. I would suggest that you use the parameters to tailor these messages, such as changing:
System.out.println("Error! Number must be greater tha 0.0");
into:
System.out.println("Error! Number must be greater than " + min);
That way, if min or max change in future , your users won't get confused :-)
I'll leave it up to you to do a similar thing for the integer input. It is your homework, after all :-)