Variable to be initialized Problem

[Shaktar Donetsk]

Below is some code for a self checkout machine. My runningtotal variable is not adding up all the numbers the user inputs. It's only outputting the most recent user input. Any help would be appreciated

double runningtot;
    Scanner input = new Scanner (System.in);
    double[]runningArray = new double[14];
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.
.
.
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for(int count=0; count < runningArray.length;  count++)
    {
     
    System.out.println("Please enter price of item: ");
    double price = input.nextDouble();
                System.out.println("");
                System.out.println("That was $" + price);
                System.out.println("");
                runningtot =+ price;
                System.out.println("Your total price is $" + runningtot);
    }

[Henry Wong]

see embedded hint....

Shaktar Donetsk wrote:Below is some code for a self checkout machine. My runningtotal variable is not adding up all the numbers the user inputs. It's only outputting the most recent user input. Any help would be appreciated

double runningtot;
    Scanner input = new Scanner (System.in);
    double[]runningArray = new double[14];
.
.
.
.
.
for(int count=0; count < runningArray.length;  count++)
    {
     
    System.out.println("Please enter price of item: ");
    double price = input.nextDouble();
                System.out.println("");
                System.out.println("That was $" + price);
                System.out.println("");
                runningtot =+ price;         //  <-------- what do you think this line does????
                System.out.println("Your total price is $" + runningtot);
    }

[Praveen Kumar M K]

Suggest you to go through Java(TM) Operators and find out about the error. Its pretty straight forward.

[Shaktar Donetsk]

Well I'm only a beginner. Is there a simple way and if so could you briefly explain it? Thanks
EDIT: This is only for a small assignment. My question is, how do I make it so runningtotal outputs the total instead of the price.
Here's a picture, it says the total is the inputted number when it should be an addition of all the prices that came before it.

[Praveen Kumar M K]

Too slow in posting my reply!

[Henry Wong]

Shaktar Donetsk wrote:Well I'm only a beginner. Is there a simple way and if so could you briefly explain it? Thanks

perhaps, this...

runningtot =+ price; 

should be written better as this...

runningtot = +price; 

Does that help yet?

Henry

[Shaktar Donetsk]

No it's still not adding. I've been trying different things for hours, this is really wierd

[Henry Wong]

Shaktar Donetsk wrote:No it's still not adding. I've been trying different things for hours, this is really wierd

The unary plus operator doesn't really do much with primatives, so "+price" is basically the same as "price",

and...

runningtot = +price;

is the same as ...

runningtot = price;

Or in other words, the runningtot is taking the value of price, because you are assigning the value of price to the runningtot variable.

Henry

[Shaktar Donetsk]

Oh. Well then how would I go about adding a users input with their previous one. Like a running total of their inputs?

[Henry Wong]

Shaktar Donetsk wrote:Oh. Well then how would I go about adding a users input with their previous one. Like a running total of their inputs?

Well, since you have been doing this for hours, what have you tried so far?

Henry

[Shaktar Donetsk]

I created a topic on another site. I've only tried the for loop and a lot of other smaller things like moving the location of 'double runningtot' because it wasn't declared locally or something along those lines. Just tinkering with things but no clear answer.

[Shaktar Donetsk]

Any suggestions or fixes would be greatly appreciated.

[Henry Wong]

Shaktar Donetsk wrote:I created a topic on another site. I've only tried the for loop and a lot of other smaller things like moving the location of 'double runningtot' because it wasn't declared locally or something along those lines. Just tinkering with things but no clear answer.

Yeah, "tinkering with things" with no clear direction is not very efficient. You should have at least have an idea of what you are tinkering with. I recommend taking a look at the Oracle tutorial, here is the pages for the operations and expressions.

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/expressions.html

perhaps it is a good place to start.

Henry

[Shaktar Donetsk]

I've got a project due soon though. I knew how to do it before but its slipped my mind. I know it's something very simple, can you show me?

[Praveen Kumar M K]

Shaktar Donetsk wrote:I've got a project due soon though. I knew how to do it before but its slipped my mind. I know it's something very simple, can you show me?

That wouldn't help you understand anything and after some time you will again face the same problem. Atleast go through the operator list through Henry's link and see whether there indeed is an operator like =+

[fred rosenberger]

Shaktar Donetsk wrote:I've got a project due soon though.

That's really not relevant to us. We're happy to help, but if you make it URGENT or stressful, folks will just walk away and not bother.

Shaktar Donetsk wrote: I knew how to do it before but its slipped my mind. I know it's something very simple, can you show me?

The link Henry provided tells you what valid operators are. look at it CAREFULLY, and see if you can find "=+" (or perhaps something that looks a lot like it).