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Why does this code keep returning a "variable might not have been initialized" error?

I'm new to coding with java, so excuse me if I come off a bit uninformed, but my code keeps returning this error for me:
Main.java:15: error: variable hold might not have been initialized
return hold;
^
My code is as follows:
public class Main
{
public static double calcPostage(double ounces)
{
double hold;
if ((ounces <= 10) && (ounces > 0))
hold = 3;
else if (ounces > 10)
hold = ((ounces-10)*0.15)+3;
else
System.out.print("Invalid input.");
return hold;
}
public static void main(String[] args)
{
double hold;
DecimalFormat form = new DecimalFormat("0.000");
Scanner input = new Scanner(System.in);
System.out.print("Enter how heavy your package is in ounces.\n");
double ounces = input.nextDouble();
System.out.print("It will cost " + form.format(calcPostage(ounces)) + " to mail your package.");
}
}
There might be some other issues in that code as I haven't been able to successfully run it just yet, but I'd truly appreciate it if someone could help me out with this. Thanks!

In the below code :
public static double calcPostage(double ounces)
{
double hold;
if ((ounces <= 10) && (ounces > 0))
hold = 3;
else if (ounces > 10)
hold = ((ounces-10)*0.15)+3;
else
System.out.print("Invalid input.");
return hold;
}
Suppose , if none of the conditions in "if" and "else if" are met, then -- double type variable hold -- doesn't gets initialized. Hence you are receiving the error :
Main.java:15: error: variable hold might not have been initialized
return hold;
^
So it is always better to initialize your variables to assign them a default value or an initial value.
Do this :
double hold = 0.0;

condition where if and else if both condition do not get satisfied else print invalid input but hold in that case is not initialized .
try to put
double hold=0.0;
so that hold get initialized.

Need to create a method to find the biggest number via an array [duplicate]

This question already has answers here:
What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?
(18 answers)
Closed 3 years ago.
I have to create a method to find the biggest number via an array.
I have tried this:
import java.util.*;
class Main {
public static void main(String[] args) {
Scanner enter = new Scanner (System.in);
int[] tab = {10,4,23,45,28,34,89,9,16,55};
int choice = 0;
do{
System.out.println("*********Menu*********");
System.out.println("1) - The biggest number : ");
System.out.println("9) - Exit :");
System.out.print("Enter your choice please : ");
choice = enter.nextInt();
switch(choice){
case 1:
System.out.println("Option 1 :");
biggest_number(big);
break;
}
} while(choice != 9);
}
public static int biggest_number(int big){
for(int i=0;i<tab.length;i++){
if(tab[i] > big){
big = tab[i];
}
}
return big;
System.out.print("The biggest number is => " + big);
}
}
I have several error messages:
Main.java:23: error: cannot find symbol
biggest_number(big);
^
symbol: variable big
location: class Main
Main.java:34: error: cannot find symbol
for(int i=0;i<tab.length;i++){
^
symbol: variable tab
location: class Main
Main.java:35: error: cannot find symbol
if(tab[i] > big){
^
symbol: variable tab
location: class Main
Main.java:36: error: cannot find symbol
big = tab[i];
^
I don't understand my errors? I have declared a parameter which is called big.
Is it return is correct also according you?
For information: I am obliged to use a method for my learning in Java.

You need to correct/change the following things in your program to make it work as you are expecting:
Pass the array itself to the method, biggest_number(...) because the scope of the array, tab is local to public static void main(String[] args) i.e. it won't be visible to the method, biggest_number(...)
Remove System.out.print("The biggest number is => " + big); after the return big; statement as it be unreachable. The program control exits the method/function after the return statement; therefore, any code after the return statement will be treated unreachable/dead which will fail compilation.
Given below is the correct program incorporating the points mentioned above:
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner enter = new Scanner(System.in);
int[] tab = { 10, 4, 23, 45, 28, 34, 89, 9, 16, 55 };
int choice = 0;
do {
System.out.println();
System.out.println("*********Menu*********");
System.out.println("1) - The biggest number : ");
System.out.println("9) - Exit :");
System.out.print("Enter your choice please : ");
choice = enter.nextInt();
switch (choice) {
case 1:
System.out.println("Option 1 :");
System.out.print("The biggest number is => " + biggest_number(tab));
break;
}
} while (choice != 9);
}
public static int biggest_number(int[] tab) {
int big=tab[0];
for (int i = 0; i < tab.length; i++) {
if (tab[i] > big) {
big = tab[i];
}
}
return big;
}
}
Output:
*********Menu*********
1) - The biggest number :
9) - Exit :
Enter your choice please : 1
Option 1 :
The biggest number is => 89
*********Menu*********
1) - The biggest number :
9) - Exit :
Enter your choice please :

The method biggest_number needs only the array as input:
static int biggest_number( int[] arr) {
if ( arr.length > 0 ) [
int big = arr[0];
for ( int i=1; i < arr.length; i++ ) {
if ( arr[i] > big ) {
big = arr[i];
}
}
return big;
}
return 0; // or throw an exception
}

As the error messages says:
You have are using the parameter big the wrong way, remove it.
you can't access the array tab from public static int biggest_number. either pass it as a parameter, or declare it as a static field.

java - create a string or integer conditions [duplicate]

This question already has answers here:
What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?
(18 answers)
Closed 5 years ago.
Building a survey application, and I am running into a roadblock with this problem. I am not understanding where my issue is exactly but when I am trying to create a two option menu, it is not allowing me to compile or run it.
errors:
Compiling 2 source files to C:\Users\martin.shaba\Documents\NetBeansProjects\Survey\build\classes
C:\Users\martin.shaba\Documents\NetBeansProjects\Survey\src\survey\Survey.java:71: error: cannot find symbol
System.out.print("Enter text for question " + (i+1) + ": ");
symbol: variable i
location: class Survey
C:\Users\martin.shaba\Documents\NetBeansProjects\Survey\src\survey\Survey.java:75: error: cannot find symbol
questions[i] = new IntegerQuestion(input.nextLine(),maxResponses);
symbol: variable i
location: class Survey
2 errors
C:\Users\martin.shaba\Documents\NetBeansProjects\Survey\nbproject\build-impl.xml:930: The following error occurred while executing this line:
C:\Users\martin.shaba\Documents\NetBeansProjects\Survey\nbproject\build-impl.xml:270: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 1 second)
Here's how I want it to be...
Choose from the following options:
S - Create a question in a string
N - Create a question in an integer
my current code:
package survey;
import java.util.Scanner;
import java.io.Serializable;
public class Survey implements Serializable
{
private String surveyName;
private Question[] questions;
private int numQuestions;
private int maxResponses;
private boolean initialized;
public Survey(String n)
{
surveyName = n;
initialized = false;
}
//initialize() sets up the numQuestions, MaxResponses, and questions for the survey
public char Questions()
{
Scanner input = new Scanner(System.in);
System.out.println("Initializing survey \"" + surveyName + "\"\n");
//add a method for password validation!?!?!? yes!!! see the bank accounts lab
System.out.print("Enter max number of responses: ");
maxResponses = input.nextInt();
System.out.print("Enter number of questions: ");
numQuestions = input.nextInt();
input.nextLine(); //have to do this to "eat" the new line character or the next input won't work correctly
System.out.println();
questions = new Question[numQuestions];
for(int i = 0; i < numQuestions;i++)
{
char choice;
//output menu options
System.out.println();
System.out.println(" S - Create String Question");
System.out.println(" N - Create Integer Question");
//loop until a valid input is entered
System.out.print("Enter choice: ");
choice = input.next().charAt(0);
//if choice is one of the options, return it. Otherwise keep looping
if(choice == 'S' || choice == 'N' )
return choice;
else
{
System.out.println("Invalid choice. Ensure a capital letter. Please re-enter.");
choice = '?';
}
(choice == '?');
return choice; //will never get here, but required to have a return statement to compile
}
System.out.print("Enter text for question " + (i+1) + ": ");
//you will also need to ask what KIND of question - right now, defaults to integer question
questions[i] = new IntegerQuestion(input.nextLine(),maxResponses);
initialized = true;
}
/*
run() gives the survey to a new survey taker, basically asks all the questions in the survey
*/
public void startSurvey()
{
if(initialized)
{
System.out.println("Welcome to the survey \"" + surveyName + "\"\n");
for(int i = 0;i < numQuestions; i ++)
{
questions[i].askQuestion();
}
System.out.println("Thank you for participating!");
}
else
{
System.out.println("Survey has not yet been setup. Please initialize first.");
}
}
/*
displayResults() displays the raw data for the survey
*/
public void Results()
{
System.out.println("Displaying data results for \"" + surveyName + "\"\n");
for(int i = 0;i < numQuestions; i ++)
{
questions[i].displayResults();
System.out.println();
}
}
/*
displayReportSummary() should run tests on your data
Examples could be: the most common response (median), the average response (mean), or display a graph of the results?
The choices are endless!
*/
public void reportSummary()
{
}
}

You're using i outside the loop. Because you declared i in the for loop, the scope of i is the loop only. It ceases to exist as soon as the loop ends.
The error messages from the compiler tell you which line of code the error is on, and exactly what the error is. It's worth learning to read these.

How to make my method accept x number of parameters [duplicate]

This question already has answers here:
When do you use varargs in Java?
(8 answers)
Closed 6 years ago.
I am faced with probably a very simple dilemma. I am trying to create a program that computes the averages, sums, and count of all numbers inputed to the calculator. The problem with this is that I can only accept one input or three (dependent on number of variables listed in my method parameters). How do I make my add() method actually accept n number of inputs as opposed to a predefined set?
Main Class
public class Calculator
{
public static void main (String [] args)
{
AverageCalculator calculation1 = new AverageCalculator();
AverageCalculator calculation2 = new AverageCalculator();
calculation1.add(13);
System.out.println("Sum: " + calculation1.getSum());
System.out.println("Count: " + calculation1.getCount());
System.out.println("Average: " + calculation1.getAverage());
System.out.println();
calculation2.add(3, 7, 12); // Error due to method parameters
System.out.println("Sum: " + calculation2.getSum());
System.out.println("Count: " + calculation2.getCount());
System.out.println("Average: " + calculation2.getAverage());
}
}
I get an error when compiling this:
Calculator.java:28: error: method add in class AverageCalculator cannot be applied to given types;
calc2.add(3, 7, 12);
I am then running into how am I going to deal with my add() method's functionality. I know what it must do, I am sure I must add a for Loop. However, there is no given length for it to parse. Do I have my i = 0; i < calculation 2; i++? See comments in this portion
Secondary Class
public class AverageCalculator
{
private int sum;
private int count;
public AverageCalculator () {}
public void add (int newNum) // One input due to single parameter
{
// How to accept the multiple input from main class with this mutator
// and successfully manipulate data in this method
sum += newNum;
count++;
}
public int getSum()
{ return sum; }
public int getCount()
{ return count; }
public double getAverage()
{ return (double) sum / count; }
}

Java supports this. Is is called "varargs". If you add "..." to your type, you can repeat it as many times as you want (including 0 times) and then, in your function, process it as an array. This could like this (this code is completely untested):
public void add(int... newNums) {
for (int num : newNums) {
sum += num;
count++;
}
}
A you can read a bit more here.

cannot find symbol (calculator) [duplicate]

This question already has answers here:
What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?
(18 answers)
Closed 5 years ago.
I recently made a program to be a calculator but three errors occurred. Here is the code:
import java.util.Scanner;
public class mathyStuff {
public static void main(String[] args) throws InterruptedException {
Scanner raw = new Scanner(System.in);
String input = raw.nextLine();
int y = 0;
while (y < input.length()) {
if (input.substring(y, y+1) == "+" || input.
substring(y, y+1) == "-" || input.substring(y, y+1) == "/" || input.substring(y, y+1) == "*") {
String x = input.substring(y, y+1);
int z1 = Integer.parseInt(input.substring(0,y));
int z2 = Integer.parseInt(input.substring(y+1, 0));
}
else {
y = y + 1;
}
}
math(z1,x,z2);
}
public static void math (int num1, String op, int num2) throws InterruptedException {
if (op == "+") {
System.out.println(String.valueOf(num1 + num2));
}
if (op == "-") {
System.out.println(String.valueOf(num1 - num2));
}
if (op == "*") {
System.out.println(String.valueOf(num1 * num2));
}
if (op == "/") {
System.out.println(String.valueOf(num1 / num2));
}
}
}
Here is the errors:
Compilation Errors Detected
Line: 18
cannot find symbol
symbol: variable z1
location: class mathyStuff
Line: 18
cannot find symbol
symbol: variable x
location: class mathyStuff
Line: 18
cannot find symbol
symbol: variable z2
location: class mathyStuff
I'm currently using a website called browxy, an online java compiler. And yes, I know. Download eclipse. I can't bring my computer everywhere I go so I use this instead.

This is a scope issue.
You can't access x, z1 and z2 because they're declared inside a while loop, but you're trying to access them outside the while loop.
You probably want to move the math function call inside the if block inside the while loop.

You are essentially asking for a variable in a situation where java can't confirm that the variable has been defined. You need to pre-define the variable in a location outside any while loops or if loops that end before the calling of these variables.
Try adding this right before the int y = 0;:
int z1 = 0;
int z2 = 0;
Also, where do you define x? If you mean the string x, you need to write "x" on line 18. If you mean a variable named x, make sure it is defined in the right scope. As it is, I can't find it anywhere.
Side note: your math method can't take "x" as an input for the second variable. It only takes "+", "-", "*", and "/". If you want to be able to use "x", you will need to change your math method.