Converting a string into double and adding it to a variable

Asked Nov 15 '16 at 21:11

Active Nov 15 '16 at 23:42

Viewed 51 times

As the title suggests, I came up with this code and I'm not sure why it doesn't do what it's supposed to do.

double value = 0;
String input;

input = scan.nextLine().toUpperCase();

    if (input.substring(0, 1) == "+") {
        value = value + Double.parseDouble(input.substring(1));
    }

Then, I typed the input "+ 25" (without the quotation marks). Also, .toUpperCase is there for another line of code; and then, printed the values to see if I got anything wrong.

System.out.println( input.substring(0, 1));
System.out.println( Double.parseDouble(input.substring(1)) );
System.out.println( value );

first one printed +

second one printed 25.0

and value printed out 0.0

Everything seems to check, why is value still 0.0?

edited Nov 15 '16 at 23:42

Nadim Baraky

asked Nov 15 '16 at 21:11

whats your input string ? – ASP Nov 15 '16 at 21:13
Your if statement is always failing, so you aren't setting `value`, so it's still 0. – azurefrog Nov 15 '16 at 21:13
2

Use `equals()` to compare values of strings. – RaminS Nov 15 '16 at 21:13
`if (input.substring(0, 1) == "+") {` this will never be true. You need to use String.equals – ControlAltDel Nov 15 '16 at 21:14
@ASP I said it, its + 25 – Nov 15 '16 at 21:21
@ControlAltDel Thanks to all of you! – Nov 15 '16 at 21:22

Converting a string into double and adding it to a variable

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