Develop Reference

Error in Pythagorean Theorem Program

I am making a Pythagorean theorem program to solve for a missing side, and if the user enters 0 as the value that means that that is the missing side to solve for. My program is not getting the correct answer. Your help is greatly appreciated.
import java.util.Scanner;
import java.lang.Math;
public class pythagTheorem {
static double a;
static double b;
static double c;
static double newa;
static double newb;
static double newc;
public static void main(String[] args) {
Scanner scan= new Scanner(System.in);
System.out.println("Enter the value of a");
a=scan.nextDouble();
scan.nextLine();
System.out.println("Enter the value of b");
b=scan.nextDouble();
scan.nextLine();
System.out.println("Enter the value of c");
c=scan.nextDouble();
scan.nextLine();
if(a==0)
{
newb=Math.pow(b, b);
newc=Math.pow(c, c);
double result=newc-newb;
newa=Math.sqrt(result);
}
System.out.println("The value of a is " + newa);
}
}

Okay! So the problem I see with this Java code would be that it doesn't necessarily follow the actual pythagorean theorem. I see that if (A==0) then execute the actual equation, but you must remember that variable A isn't the hypotenuse of the triangle!
A^2 + B^2 = C^2 (C being the hypotenuse) If you want to make it so that it finds any part of the triangle you must remember to derive the equation so that you can find the missing side! Such as, you have side A and C but you want to find side B, the equation would then be B^2 = C^2-A^2.
Last of all, I see you have newb=Math.pow(b, b); that would power your variable to itself! Even the the powers are only 2, so it would be newb=Math.pow(b, 2);
TIP! Remember to capitalize the second word in a variable name like numa to numA
/* REMEMBER THAT A NUMBER MUST NEVER BE GREAT THAN C UNLESS IT IS THE UNKNOWN OR YOU WILL ENCOUNTER A NONREAL NUMBER BECAUSE YOU CAN'T SQUARE ROOT A NEGATIVE NUMBER*/
import java.util.Scanner;
import java.lang.Math;
public class pythagTheorem {
static double a;
static double b;
static double c;
static double newa;
static double newb;
static double newc;
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Enter a ZERO for the unknown side!");
System.out.println("Enter the value of side A :: ");
a = scan.nextDouble();
System.out.println("Enter the value of B :: ");
b = scan.nextDouble();
System.out.println("Enter the value of C :: ");
c = scan.nextDouble();
if (a == 0) {
newc = Math.pow(c, 2);
newb = Math.pow(b, 2);
newa = Math.sqrt(newc - newb);
System.out.println("Your missing side is :: " + newa);
}
else if(b == 0){
newc = Math.pow(c, 2);
newa = Math.pow(a, 2);
newb = Math.sqrt(newc - newa);
System.out.println("Your missing side is :: " + newb);
}
else if(c == 0){
newa = Math.pow(a, 2);
newb = Math.pow(b, 2);
newc = Math.sqrt(newa + newb);
System.out.println("Your missing side is :: " + newc);
}
else
System.out.println("Sorry! There is an error!");
}
}

Class, interface, or enum expected error

I have tried just about everything I can think of to fix my error but I;m completely stumped. I keep getting a "class, interface, or enum expected" error. What am I missing?
import java.until.*;
public class FutureValues {
public static final Scanner CONSOLE = new Scanner(System.in);
public static void main(String[] args) {
System.out.println("Lab 3 written by JENNIFER ADAME");
System.out.println();
//declare variables
double p;
double r;
double y;
double f;
System.out.print("Enter present value: ");
double p = console.nextDouble( );
System.out.print("Enter interest rate: ");
double r = console.nextDouble( );
System.out.print("Enter number of years: ");
double y = console.nextDouble( );
double f = compoundInterest(p, r, y);
System.out.print("The future value is" + f);
}
public static double compoundInterest (double p, double r, double y) {
double f = p * Math.pow(((1 + r) / 100), y);
return f;
}
}
}
If anyone could help that would be awesome!

You are adding one extra brace '}' at the end...just remove it
If wanna keep safe from these kind of errors in future,consider formatting your code properly.(Use Ctrl+shift+f for eclipse and Alt+shift+f for netbeans)

There is a mismatched brace at the end of your file.

Numbers to an extreme (Java)

EDIT: HERE IS A SCREENSHOT OF THE OUTPUT
https://www.dropbox.com/s/93d09a627se3b1u/Screenshot%202015-09-16%2019.08.19.png?dl=0]
I was recently asked to make a program that can calculate and display...
1 / (1!) + 1 / (2!) + . . . 1 / (n!)
using the Scanner utility. I seem to be having a lot of trouble with this. the program itself works, but it somehow gives the same answer no matter what number I input. Here's what I have so far (And yes, it is purposely incomplete, I'm stumped).
import java.util.Scanner;
class Power2
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("I will calculate 1/(1!) + 1/(2!) . . . +
1/(n!)\nWhat is the value of n?");
Double n = input.nextDouble();
Math(n);
System.out.println("e = " + Math.E);
}
public static void Math(Double E)
{
Double product = 1.0;
int x = 0;
while (E > 0)
{
product = product * E;
E--;
}
Can anyone give me a way to finish/solve this problem? Thanks a ton.
~Andrew
EDIT: This code works fine for just finding the extreme. I will work on a way to add the preceding components of the equation to this, but It's a bit tricky for me.
import java.util.Scanner;
class Power2
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("I will calculate 1/(1!) + 1/(2!) . . . +
1/(n!)\nWhat is the value of n?");
Double n = input.nextDouble();
Math(n);
System.out.println("e = " + Math(n));
}
public static Double Math(Double E)
{
Double product = 1.0;
while (E > 0)
{
product *= E;
E--;
}
return product;
}
}

You are confused with too much Math.
You've got your method Math with a parameter E and the Java Math class with a constant E. You're mixing them up.
Try
public static double factorial(double v)
{
double product = 1.0;
while (v > 0)
{
product *= v;
v--;
}
return product;
}

Your code:
System.out.println("e = " + Math.E);
Math.E is a constant - it will always print the euler number hence your output.
To call the the method correctly it should be
System.out.println("e = " + math(e)"
Input 1 - Output 1
Input 2 - Output 1.5
Input 3 - Output 1.66666667
import java.util.Scanner;
class MyClass
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("I will calculate 1/(1!) + 1/(2!) . . . + 1/(n!)\nWhat is the value of n?");
double n = input.nextDouble();
double solution = doMath(n);
System.out.println("e = " + solution);
}
public static double doMath(double n) {
double ret = 0;
// the number of terms we add
for (int i = 1; i <= n; i++) {
ret += calcFaculty(i);
}
return ret;
}
// calculate every single term
public static double calcFaculty(double d){
double calc = 1;
for (int i = 1; i <= d ; i++) {
calc = calc* 1/i;
}
return calc;
}
}

Hi Andrew the program always return the same number
e = 2.718281828459045
Because the line System.out.println("e = " + Math.E); is not calling the method Math but calling to the class java.lang.Math. I dont know if is this what you find dubious.

Identifier expected in java

I wrote a simple program in java:
public class Will {
int static square(int x) {
int y = x * x;
return y;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Please enter a number...");
int n = sc.nextInt();
int result = Will.square(n);
System.out.println("Square of " + n + " is " + result);
}
}
When I try to compile it, I'm getting those errors:
square.java:6: error: <identifier> expected
int static square (int x)
^
square.java:6: error: invalid method declaration; return type required
int static square (int x)
^
2 errors
How to resolve those?

It has to be:
static int square (int x)
i.e the return-type has to be after the access-modifiers and before the method name.

Change it like
public/private/protected(Access specifier) static int square(int x)
as per JAVA standard rules

Cannot read the decimal point in Scanner

import java.util.Scanner;
public class Assignment3 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
double pi = 3.142;
double T, v, a, x, r;
System.out.println("3.Centrifuge. The rotor of an ultracentrifuge rotates at x rev/s.");
System.out.println("A particle at the top of the test tube is r meter from the rotation axis.");
System.out.println("Calculate it’s centripetal acceleration.");
System.out.printf("Enter the number of rotation in rev/s : ");
x = input.nextInt();
System.out.printf("Enter the distance in meter : ");
r = input.nextInt();
T = 1/x;
v = (2*pi*r)/T;
a = (v*v)/r;
System.out.println("\n\nAnswer");
System.out.printf("The centripetal acceleration is : %.2f m/s^2\n", a);
}
}
Hi all. This is my coding and it cannot run when I put decimal point. how to fix it?

Replace input.nextInt(); with input.nextDouble();
x = input.nextInt(); // It will simply ignore decimal values
Hence you need to use nextDouble()
x = input.nextDouble(); // This will read the entire decimal value

You read a int with
input.nextInt();
Try
input.nextDouble();

Try it.
import java.util.Scanner;
public class JavaScannerDouble {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String data = input.next();
double decimalValue = Double.parseDouble(data);
System.out.println("Decimal value : " + decimalValue);
// test of decimal value
double response = decimalValue / 0.1;
System.out.println("response : " + response);
}
}