java problem

[KateP]

Hello; i'm trying to build a java calculator application; I keep getting errors
when i compile; this is the error:

---------------------------------------------------------------------

C:\javap>javac Calc.java
Calc.java:46: variable result might not have been initialized
System.out.println("Answer= " + result);
^
1 error

---------------------------------------------------------------------

and this is the code; mind you i AM a beginner, so any help AT ALL would
be great.

--------------------------------------------------------------------

public class Calc
{

public static void main(String[] args)
{

String another = "y";

while(another.equalsIgnoreCase("y"))
{
System.out.println("Enter the first number: ");
int first = Keyboard.readInt();

System.out.println("Enter operator (+, -, * or /): ");
int op = Keyboard.readInt();

System.out.println("Enter second number: ");
int second = Keyboard.readInt();

int result;

switch(op)
{
case '+':
result = first + second;
break;

case '-':
result = first - second;
break;

case '*':
result = first * second;
break;

case '/':
result = first / second;
break;

default:
System.out.println("Wrong operator; use +, -, *, or / functions");

};
System.out.println("Answer= " + result);
System.out.println("Another calculation? (y/n) ");
another = Keyboard.readString();


}

}

}

-----------------------------------------------------------------

basically what it's meant to do is ask the user for a number, then an operator,
then a number than give an answer. if the user wants to make a another calculation,
s/he pressed "y" and it goes through again.

the problem i have (apart from the error ) is that i dont know how to allow
for multiple calculations:

eg; 4-3+34=blah or 56*6-12=blah

please help me!

[JavaBeg]

The varialble "result" has to be initialised to zero or some other integer
value
int result = 0;

Hope this helps
============================


"KateP" <java.@127.0.0.1> wrote:
>
>Hello; i'm trying to build a java calculator application; I keep getting
errors
>when i compile; this is the error:
>
>---------------------------------------------------------------------
>
>C:\javap>javac Calc.java
>Calc.java:46: variable result might not have been initialized
>System.out.println("Answer= " + result);
>^
>1 error
>
>---------------------------------------------------------------------
>
>and this is the code; mind you i AM a beginner, so any help AT ALL would
>be great.
>
>--------------------------------------------------------------------
>
>public class Calc
>{
>
>public static void main(String[] args)
>{
>
>String another = "y";
>
>while(another.equalsIgnoreCase("y"))
>{
>System.out.println("Enter the first number: ");
>int first = Keyboard.readInt();
>
>System.out.println("Enter operator (+, -, * or /): ");
>int op = Keyboard.readInt();
>
>System.out.println("Enter second number: ");
>int second = Keyboard.readInt();
>
>int result;
>
>switch(op)
>{
>case '+':
>result = first + second;
>break;
>
>case '-':
>result = first - second;
>break;
>
>case '*':
>result = first * second;
>break;
>
>case '/':
>result = first / second;
>break;
>
>default:
>System.out.println("Wrong operator; use +, -, *, or / functions");
>
>};
>System.out.println("Answer= " + result);
>System.out.println("Another calculation? (y/n) ");
>another = Keyboard.readString();
>
>
>}
>
>}
>
>}
>
>-----------------------------------------------------------------
>
>basically what it's meant to do is ask the user for a number, then an operator,
>then a number than give an answer. if the user wants to make a another calculation,
>s/he pressed "y" and it goes through again.
>
>the problem i have (apart from the error ) is that i dont know how to allow
>for multiple calculations:
>
>eg; 4-3+34=blah or 56*6-12=blah
>
>please help me!
>
>

The first response is not fully correct. It does not "have" to be initialized
to zero or any other value explicitly. It will automatically be initialized
to zero when declared.

The problem is that this is a local variable and you used it outside it's
scope. If you want to use this variable at the point you are using it, you
need to declare it as a global variable.




"KateP" <java.@127.0.0.1> wrote:
>
>Hello; i'm trying to build a java calculator application; I keep getting
errors
>when i compile; this is the error:
>
>---------------------------------------------------------------------
>
>C:\javap>javac Calc.java
>Calc.java:46: variable result might not have been initialized
>System.out.println("Answer= " + result);
>^
>1 error
>
>---------------------------------------------------------------------
>
>and this is the code; mind you i AM a beginner, so any help AT ALL would
>be great.
>
>--------------------------------------------------------------------
>
>public class Calc
>{
>
>public static void main(String[] args)
>{
>
>String another = "y";
>
>while(another.equalsIgnoreCase("y"))
>{
>System.out.println("Enter the first number: ");
>int first = Keyboard.readInt();
>
>System.out.println("Enter operator (+, -, * or /): ");
>int op = Keyboard.readInt();
>
>System.out.println("Enter second number: ");
>int second = Keyboard.readInt();
>
>int result;
>
>switch(op)
>{
>case '+':
>result = first + second;
>break;
>
>case '-':
>result = first - second;
>break;
>
>case '*':
>result = first * second;
>break;
>
>case '/':
>result = first / second;
>break;
>
>default:
>System.out.println("Wrong operator; use +, -, *, or / functions");
>
>};
>System.out.println("Answer= " + result);
>System.out.println("Another calculation? (y/n) ");
>another = Keyboard.readString();
>
>
>}
>
>}
>
>}
>
>-----------------------------------------------------------------
>
>basically what it's meant to do is ask the user for a number, then an operator,
>then a number than give an answer. if the user wants to make a another calculation,
>s/he pressed "y" and it goes through again.
>
>the problem i have (apart from the error ) is that i dont know how to allow
>for multiple calculations:
>
>eg; 4-3+34=blah or 56*6-12=blah
>
>please help me!
>
>