String To A Double In Scanner - Performing Calculation?
Apr 23, 2015
This may be a multipart question. Basically I have to write a program that accepts a string, converts it to a double splits it and then performs a calculation.
public static void main(String[] args) {
String input = ""; // initalize the string
boolean isOn = true; // used for the while loop...when false, the program will exit.
String exitCommand = "Exit"; // exit command
String[] token = input.split(("(?<=[-+*/])|(?=[-+*/])"));
[Code] ....
This is the error I get:
Enter a math problemException in thread "main" java.lang.NumberFormatException: empty String
at sun.misc.FloatingDecimal.readJavaFormatString(Floa tingDecimal.java:1842)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecim al.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at Calculator.main(Calculator.java:22)
[Code] .....
How do I go about actually fixing it. Without that line commented out I get this:
Enter a math problem
2+2 <-What I entered
[Ljava.lang.String;@135fbaa4
Also, how would I go about using the submethods to check for valid operands and operators (also part of the problem) I have the actual lists made obviously, but am unsure how to get those to work with the problem.
I am new Java Programming and I am struggling to pass my Java class. How to perform Java but I am trying. For this particular assignment I supposed to:
* Change all variables' data types to double. * Change the two prompts to request double values * Change change the two calls to the nextInt() method to nextDouble().
This is the original assignment:
import java.util.Scanner; public class ArithmeticDemo { public static void main(String[] args) { Scanner input= new Scanner(System.in); int firstNumber; int secondNumber; int sum; int difference; int average;
I am new to programming, but am working on a program that takes 6 inputted grade averages on a scale of 0.0 - 100.0 (exceptions in the case someone has exceeded the traditional 100.0 limit) and then divides it by 6 and returns the value in a dialog box. However, I want to take the values inputted and convert them to a 4.0 scale (90.0-100.0 = 4.0, 80.0-89.99 = 3.0, etc.) and then get the average of that so that I can return an average on a 4.0 scale. I have been trying to accomplish. Also, as of right now my program only prompts the user for 6 inputs, but I'd like the user to be able to input as many as he/she would like to, I am pasting the code I currently have below.
import javax.swing.JOptionPane; public class GPA_Calculation1_0 { public static void main(String[] args) { String courseOne = JOptionPane.showInputDialog("Enter numeric GPA of Course One: ");//Course one double numOne = Double.parseDouble(courseOne);
for (int i = 0; i < letters.length; i++) { double relativeFreq = (onesAverage()/letters[i]); char a = characters.charAt(i); double j = score[i]; System.out.printf();//ToDo
Above is my current code. Basically- There is a string called characters of length 26 (1 char for each letter in alphabet), a double relativeFrequency value which does a calculation and the end result is a number with lots of decimal numbers. The score array has set double values within the array.
What I want to do is create a print f statement where I print out each of the values I initialized above WITH specific amounts of spaces in between. So it should be in this order:
a (spaces) j (spaces) relativeFreq (newLine).
Between J and relativeFreq there should be 4 spaces, however if the value in relativeFreq is greater than 10 (it won't be greater than 100)- then there should be 3 spaces. Everytime I try to create a printf statement my code ends up crooked for some of the values.
for (int i = 0; i < letters.length; i++) { double relativeFreq = (onesAverage()/letters[i]); char a = characters.charAt(i); double j = score[i]; System.out.printf("%c %.4s %.4s%n",a, j, relativeFreq);
package rockjava; import java.text.NumberFormat; import java.util.Scanner; public class file4 { public static void main(String[] args)
[Code] ....
Please Input Num of Pods + Num of Keys= 20.5 Exception in thread "main" java.util.InputMismatchException at java.util.Scanner.throwFor(Unknown Source) at java.util.Scanner.next(Unknown Source) at java.util.Scanner.nextFloat(Unknown Source) at alijava.file4.main(file4.java:14)
(It is not accepting double values. However working fine for integers.)
//Scanner Test String stream2 = "ab34ef 56"; // create a new scanner with the specified String Object Scanner scanner = new Scanner(stream1); // find a string "World"
[Code] ....
Matched expression found by findInLine: 34
ef56
is new line? right?
The java.util.Scanner.nextLine() method advances this scanner past the current line and returns the input that was skipped. This method returns the rest of the current line, excluding any line separator at the end.
then 56 is in new line and it must return ef.What is the problem?
How does the Scanner goes through the String which is passed to it as a parameter. For example, String input = "222 dddd 222 ddd22" is passed to the method and here's the code:
Java Code:
public static void sum(String anything) { Scanner input = new Scanner(anything) while(input.hasNext()) { if(input.hasNextDouble()) { double nextNumber = inut.nextDouble(); sum += nextNumber } ...... ...... } mh_sh_highlight_all('java'); {
So, how does Scanner calculates a passed String? I just want to know the way it calculates/reads.
I'm having an issue, I have a scanner (Scan.nextLine();) that scans the console for input to fetch the string "word". Then I want to fetch a character using Scan.findInLine(word).charAt(number);. The problem is that the console requires me to write 2 lines in order for the program to move on. I only want the program to scan for a word, and then move on with what it has instead of requiring 2 inputs.
The project is a program that allows the user to enter students and enter grades for each student. One of the requirements is that if there is already a grade stored for the student that it will display the previous grade. IF the user then enters a new grade the new grade will be stored. IF the user simply presses enter (enters an empty string) nothing is done. I have everything working except for the requirement of doing nothing if the user enters an empty string. If I just press enter at this point I get a NumberFormatException.
The below code is a method "setTestGrades" from the student class. This method iterates through each student object stored in an array list and then checks if there is a previous grade (Requirement# unset grades have to default to -1) before allowing the user to set a new grade.
public void setTestGrades(int testNumber) { //Sets the grade for the specified test number for each student in the arraylist. testNumber -= 1; Scanner input = new Scanner(System.in); for (int i = 0; i < studentList.size(); i++) { System.out.println("Please enter the grade for Test #" + (testNumber + 1) + " For Student " + studentList.get(i).getStudentName());
I am trying to convert the double 4270571936.0000000000d to a hex string using Double.toHexString() and the answer I'm getting is 0x1.fd17834p31, what does p stands for?
The answer I'm expecting to get is 0x41efd17834000000 so not sure why it won't give me the correct answer?
The following floating point Double to hex calculator shows the write answer right Floating Point to Hex Converter
//Students Full Name firstName = JOptionPane.showInputDialog("Enter student " + "first name."); lastName = JOptionPane.showInputDialog("Enter student " + "last name."); // Get test grade (numbers) [b]test1 = JOptionPane.showInputDialog("Enter test1 grade")[/b];
The line in bold is where that error comes up. I know it something simple but I can't remember. I declared both firstName and lastName as Strings and then the test1 I declared as double. I had a similar error in a previous assignment where I had a integer(age) input and then i had an output statement asking for a name all I needed to do was put keyboard.nextLine(); after my age input and I was fine.
I am making a program where the user types in how many students, the student name and the student result. My problem is typing in a dobule name for instance: Tom Tom.
I have tried both:
String name = input.Next(); -> Only works with one name. and String name = input.nextLine(); -> Skips right trough and ask me to type result again.
Here is my code:
Java Code:
import java.util.Scanner; public class c5e8 { public static void main(String[]args){ Scanner input = new Scanner (System.in); int highestResult = 0; String highestName = " ";
I'm having an issue with figuring out how to structure and call a method using a string prompt. My prof has given us specific methods to create, and the one I'm having issues with is blic static double getOperand(String prompt). What I have currently is this:
public static double getOperand(String operand1, String operand2){ Scanner input = new Scanner(System.in); System.out.println("What is the first operand?"); operand1 = input.toString();
System.out.println("What is the second operand?"); operand2 = input.toString(); return operand1, operand2; }
which is obviously not working. When I asked my prof he sent me this, "The String paramater in the getOperand() method is intended to have the prompt value that is passed to it. Within the method, the prompt is then displayed, what the prompt is asking for is input, and then returned to the method call.For example, if the method is public double getOperand(String prompt) within the method you would display the prompt, as in System. out. println(prompt), use the Scanner class to create an object, perhaps called input, and then use the input object to get the value asked for by the prompt. Once you have that value, which in this example would be a double, then return the value to the method that called it.
The call could be something like this: double value = getOperand("What is the first operand?");". But that only works a little. Clearly I'm missing something and no matter what I google, or how many times I read the chapter, I am just not getting this. Everything else up to this point has been easy. and I can create regular methods just fine, the menu method works, but I can't figure out this string method and all the rest build off this method.
I am supposed to write a program on PuTTY using UNIX (I have Windows 8), but I am not comfortable with it yet, so I am using Java through NetBeans (IDE 7.4).
The program has to follow these instructions (ignore the Linux part of the instructions, the rest is in bold):
Write a program on the Linux system using the putty utility. The program should get strings of data from the command line (that is, look for the data in the "args" array of strings). Use a loop to convert each of the strings in the array into a double and add the number to a total. Print the total after all of the strings have been processed.
The program will use try-catch to catch any error that occurs. If an error occurs, the program will print a message saying that the error occurred. The program can end at that point.
You should create the Java program using the nano editor. The input data should be a list of numbers on the line that runs the program.
The problem so far is that I keep getting an error when converting a String value into a new double value. I have yet to code the try-catch method in my program
Java Code:
import java.util.*; public class Program13Strings { public static void main(String[] args) { Scanner scan = new Scanner (System.in); System.out.println("How many lines of data do you wish to enter?"); int size = scan.nextInt();
[Code] ....
*NOTE: right where my code says double newDouble = Double.valueOf(newResponse); is where the error is occurring.
*ERROR: Exception in thread "main" java.lang.NumberFormatException: For input string: "abc"
at sun.misc.FloatingDecimal.readJavaFormatString(Floa tingDecimal.java:1241) at java.lang.Double.valueOf(Double.java:504) at program13strings.Program13Strings.main(Program13St rings.java:21)
I have a double primitive and gave it a huge value. I am curious if valueOf could ever potentially cause data loss. I tried a simple test and it seems it never loses any data:
Java Code:
public class DoubleStringTest { public static void main(String[] args) { double val = 1029.129348558634; System.out.println(val); System.out.println(String.valueOf(val)); } } mh_sh_highlight_all('java');
I am working with java project which is kind of charting room..but the problem is when am writing the query for listing the message in the conversation the error prevail in my eclipse...string literal is not properly closed by double quote...this is my java file
I am working on a project that just calculates simple interest based upon a principal and a percent interest rate written as .xxxx from user.
I need the Loan amount and the final interest calculation to show up as a currency with commas in appropriate areas, the Rate to be expressed as X.xxx% instead of .xxxx
I keep getting this error when I compile:
C:JavaInterestCalculator.java:46: error: incompatible types: String cannot be converted to double principal = formatter.format(principal); ^ C:JavaInterestCalculator.java:49: error: incompatible types: String cannot be converted to double rate = formatter.format(rate); ^ C:JavaInterestCalculator.java:52: error: incompatible types: String cannot be converted to double totalInterest = formatter.format(totalInterest); ^ 3 errors
Tool completed with exit code 1
And here is my code
import java.util.Scanner; import java.text.NumberFormat; import java.text.DecimalFormat; // class declaration public class InterestCalculator { // main method declaration
I am trying to make a program that calculates the change due in dollars and cents. The user inputs both the amount due and the amount tendered. My program only works with whole numbers?
I am writing a code in which a user inputs data as a string and that data must be verified as a valid number. A valid number is anything from 0-100. Then all valid numbers are converted into double numbers.
I am having trouble in how to write the validation part of the code.
Is it suppose to be an if, else statement? And if so how is it suppose to be validated?
I have some problems about performing regular expression. In the following code, the output as a result is being "valid last name". But in my opinion, it should be "invalid last name". Because "Doe" has not any space, apostroph or any hypen. Look at the regular expression statement: "[a-zA-Z]+([ '-][a-zA-Z]+)*"
package deneme; public class Deneme { public static void main(String[] args) { String lastName = "Mc-Something"; // Mc-Something if(!lastName.matches("[a-zA-Z]+([ '-][a-zA-Z]+)*")) System.out.println("Invalid last name"); else System.out.println("Valid last name"); } }
I know that the asterisk qualifier means character(s) in any number.(Is this wrong?) So for "Mc-Something", 'M' corresponds to [a-zA-Z], 'c' corresponds to +, - corresponds to [ '-], 'S' corresponds to [a-zA-Z], "o" corresponds to +, and finally "mething" corresponds to *, doesn't they? But for "Doe", there is no any space, apostroph or hypen.
