My verify method also always returns false. So I'm given three classes to begin with. Calculator, Expression, and InfixExpression and they are listed below.
The goal is to create a class called PostfixExpression that extends Expression and can read and calculate postfix expressions.
My evaluate() method works for most calculations but when it needs to return a negative value it just returns the positive equivalent.
Also, my verify method always returns false and I can't pinpoint why.
Here's my current code. Some things are commented out for debugging purposes.
import java.util.Scanner;
/**
* Simple calculator that reads infix expressions and evaluates them.
*/
public class Calculator
{
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
So I am working on a PostFix calculator that is used in command line for a class project, and I am having a little trouble on developing a memory for it. I have been told to create a hashMap and I have researched it and understand the basics of it. I have the calculating method working, but what I am having trouble trying to implement a way for the user to declare variables. For example this what the user should be able to do:
> a = 3 5 + 1 - 7 > bee = a 3 * 21 > a bee + 28
[code]....
I just need to be able to save the answers as a variable the User names, such as the example and let the user be able to use the variables later.
Create an integer array with 10 numbers, initialize the array to make sure there are both positive and negative integers. Write a program to generate two arrays out of the original array, one array with all positive numbers and another one with all negative numbers. Print out the number of elements and the detailed elements in each array.
public class problem3 { public static void main(String[]args){ int[] numbers = {1, 2, 3, 4, 5, -1, -2, -3, -4, -5}; for (int i = 0; i<numbers.length;){ if(i>0){ System.out.println(numbers); } else System.out.println(numbers); } } }
Basically I'm trying to compute the standard deviation for a set of numbers and I'm using previously know data to compute this. The data I'm working with is here (note all of this is fake as its for an assignment):
Next this is the code that I know is producing the error:
/** * Pass in original data from files, and pass in computed grades as arraylist. this returns all of the standard deviations to be printed */ public static ArrayList calcStandDev(String data1[], ArrayList<Double> grades, ArrayList<Integer> averages) { double standDev = 0; int j = 0; //gets rid of first element in string array, makes processing MUCH easier String[] data = Arrays.copyOfRange(data1, 1, data1.length);
[Code] ....
Look for the line with all the ***'s, it is producing the "java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Integer".
The reason I dont undersand why its producing this error is because temp.get(i) should be a integer - averages.get(i) (is type double), I do believe automatic up casting is present here making them both a double then I multiply it by itself producing a double? I dont understand where the casing is occurring. And just incase you want the formula I'm using for standard deviation here it is:
I am very new to Java. I have been working for a couple months on a program for school. It has not gone well. I finally was able to scrap together a working program, but i left something out that needs to be. I have to include input validation to check for negative values, prompting users to re-enter values if negative. I have included my current code, the program works perfectly, but what to do about the negative numbers.
Java Code:
package gradplanner; import java.util.Scanner; public class GradPlanner { public static void main(String[] args) { Scanner input = new Scanner(System.in); int numofclasses = 0; int totalCUs = 0;
I am very new to Java. I have been working on a program. It has not gone well. I finally was able to scrap together a working program, but i left something out that needs to be. I have to include input validation to check for negative values, prompting users to re-enter values if negative.I have included my current code, the program works perfectly, but what to do about the negative numbers.
package gradplanner; import java.util.Scanner; public class GradPlanner { public static void main(String[] args) { Scanner input = new Scanner(System.in); int numofclasses = 0;
I'm having some issues getting this code to reject negative numbers. What I'm doing wrong.
import java.util.Random; import java.util.Scanner; public class ForLoop { public static void main (String [] args) { Random randomNumber = new Random();
I've been writing a fraction class code below that does a number of arithmetic calcs and when I run it these are the results I get. My gcd doesn't work when it comes to negative fractions and I'm not quite sure how to print.out the boolean methods ((greaterthan)), ((equals))and ((negative)). I'm also not sure if I have implemented those 3 methods properly. I'm still learning how to do unit testing.
Enter numerator; then denominator. -5 10 -5/10 Enter numerator; then denominator. 3 9 1/3 Sum: -5/30 -0.16666666666666666 Product: -5/30 -0.16666666666666666 Devide: -15/30 -0.5 subtract: -45/90 -0.5 negative: 1/6 0.16666666666666666 Lessthan: 1/6 0.16666666666666666 greaterthan: 1/6 0.16666666666666666
FRACTION CLASS
import java.util.Scanner; public class Fraction { private int numerator; //numerator private int denominator; //denominator
You are to design a Java application to carry out additions and subtractions for numbers of any length. A number is represented as an object which includes a sign and two strings for the whole and decimal parts of the number. And, the operations must be done by adding or subtracting characters directly. You are not allowed to convert these strings to numbers before the operation.
The program must use a "Number" class which includes at least the following methods:
Number ( ); Number (double n); Number add (Number RHS); Number subtract (Number RHS); String toString ( );
This is what i have but it only adds positive numbers and it doesn't subtract problems like 7.05-8.96. Also some of it was what our teacher gave us like alignwhole method
import java.util.Scanner; public class Number{ private String whole; private String decimal; private String sign; public static void main (String[] args){ System.out.println("Enter two numbers");
You are to design a Java application to carry out additions and subtractions for numbers of any length. A number is represented as an object which includes a sign and two strings for the whole and decimal parts of the number. And, the operations must be done by adding or subtracting characters directly. You are not allowed to convert these strings to numbers before the operation.
The program must use a "Number" class which includes at least the following methods:
Number ( ); Number (double n); Number add (Number RHS); Number subtract (Number RHS); String toString ( );
The below code is what our teacher gave us to start with, but it needs to add and subtract positive or negative numbers of any length. This code only adds positive numbers. Need to write code for subtraction .
Java Code:
import java.util.Scanner; public class Number{ private String whole; private String decimal; private String sign;
So I have re-written the code but it is still not running correctly. Any number i type in it throws an exception, also i need the program to add the totals that i type in and then once i type -1 into the prompt button list all the number i typed in and give me the average.
import java.awt.*; import java.awt.event.*; import javax.swing .*; import javax.swing.text.*; public class Averages extends JFrame { //construct components JLabel sortPrompt = new JLabel("Sort By:");
I would like to create a program that takes some files and modifies them in this way: The files should contain text formatted in this way:
############## #various comments# ############## something{ identifier=1234 anotherIdentifier=1235 anotherOne=12345 //and so on... }//I need only this
#Comments are sometimes made this way
somethingAgain{ #comments that explains what's below them I:dentifier:something, I, do, not, need #see ^that A:notherIdentifier:boolean //and so on.. }
And I have to make so that the numbers contained in something{} in all the files don't match. I could ask to make so that the input file is only one, and it is formatted this way:
identifier=1234 anotherIdentifier=1235 anotherOne=12345 //and so on...
but I don't know how to do the rest of the program... That's what I've done (the names of the classes, package etc. are in Italian and there's some useless code that NetBeans prevents me from deleting):
package confronto; import java.awt.Color; import java.io.*; import javax.swing.*; public class confrontoTesti extends javax.swing.JFrame {
So I was making a Java Calculator that only adds. The problem is that the numbers are not adding. I think it is because whatever has been clicked is not being saved to be added.
I want a simple jsp page that performs basic operations on numbers such as addition, subtraction, multiplication, division and modulus . How to run that file?
I am new to java and during my classes we built a basic calculator. I want to extend my calculator and added function to square numbers.Here is my program:
How can I make the numbers to stay at the textfield of my calculator instead of disappear like when I type 1 then hit the + sign the number 1 disappears from the textfield I would like to have this (1+1) showing in the text field and also if try to press only + , * , - , / to show error.
Case study : infix to postfix conversion, i don't really know how i could make codes, I can understand what is the meaning of infix and postfix but when it comes of making codes i really have a hard time with it.
after i am done calculating everything from numbers stack, i pop the last number and return it... my question is how can i catch an exception if the size of my numbers stack is greater than 1;
public static String evaluate(String input) { char[] a = input.toCharArray(); if (input.isEmpty()) return "No input"; else if (input.equals(" ")) return "No input"; else if (input.equals(" "))
I need to convert infix To Postfix but have a few errors.
Error msg:
PostFix: Exception in thread "main" java.util.EmptyStackException at java.util.Stack.peek(Unknown Source) at java.util.Stack.pop(Unknown Source) at assignment4.infixToPostfix.evaluatePostfix(infixTo Postfix.java:129) at assignment4.infixToPostfix.main(infixToPostfix.jav a:19)
NB: 129 >>return (double) s1.pop(); AND 19>>>double ans = evaluatePostfix(postfixStr); Deadline = less than 1 hour
My question is to evaluate a Postfix notation entered from keyboard. I have no errors in my code but it prints only :
Exception in thread "main"
java.util.NoSuchElementException at ArrayStack.pop(PostFixEvaluation.java:72) at PostFixEvaluation.evaluatePostfix(PostFixEvaluatio n.java:107) at PostFixEvaluation.main(PostFixEvaluation.java:140)
I tried many values but it prints the same exception all the time.
So my code works perfectly when I input (a+(c-d) and i get ab+cd- for postfix and *+ab-cd for prefix. However when I input a+b+c for infix i receive abc++ postfix and +a+bc prefix when its supposed to be ab+c+ postfix and ++a b c prefix. So my issue is that any infix input with parenthesis, it converts them correctly, however without parenthesis it does not convert correctly.
import java.util.*; public class stack { public static char[] convertToPostfix(char[] infixEx) { Stack<Character> operatorStack = new Stack<Character>(); char[] postfix = new char[infixEx.length]; int index = 0;
