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breaks in converting String to Integer

 
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Can anyone please help when I was debugging that it does not go after I wanted to make an Integer from String and it breaks here I cannot see the problem. The test is below





The output is :


22+33 = 55
+33 = 55
number is:


However I wanted it to be number is: 22. Thank you in advance=)


 
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How this code is running. I am even not able to compile the code.

and also it gives the java.lang.ClassCastException when I correct and run the code.
 
Manoj Kumar Jain
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Look how you initialized "numbers" and what values are you placing value in it ??

Can you type cast the result of numbers.get(d) to an String object ?
 
Anissa Pary
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Manoj Kumar Jain wrote:Look how you initialized "numbers" and what values are you placing value in it ??

Can you type cast the result of numbers.get(d) to an String object ?


Ok, thanks get it.=) It is because of char=///
 
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There is a much simpler way to find out whether a char represents a digit or 0.
And don’t write if (...) return true; else return false;Yes, you can do arithmetic with chars, because, contrary to popular belief they are not letters. They are numbers. '0' is stored as (I think) 0x30 = 48decimal. '0' to '9' are a consecutive sequence, so you can use that trick.
There is also a method in the Character class which does the same thing.
 
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Campbell Ritchie wrote:There is a much simpler way to find out whether a char represents a digit or 0.
And don’t write if (...) return true; else return false;Yes, you can do arithmetic with chars, because, contrary to popular belief they are not letters. They are numbers. '0' is stored as (I think) 0x30 = 48decimal. '0' to '9' are a consecutive sequence, so you can use that trick.
There is also a method in the Character class which does the same thing.



That's a neat trick. I couldn't resist playing around with this one, too, but I went another direction.


Now the test becomes:
 
Manoj Kumar Jain
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yes, this trick is good if we need to look for a specific characters instead of consecutive digits/chars. This provide more flexibility to check for the characters appearing in the String/Input.
 
Anissa Pary
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Campbell Ritchie wrote:There is a much simpler way to find out whether a char represents a digit or 0.
And don’t write if (...) return true; else return false;Yes, you can do arithmetic with chars, because, contrary to popular belief they are not letters. They are numbers. '0' is stored as (I think) 0x30 = 48decimal. '0' to '9' are a consecutive sequence, so you can use that trick.
There is also a method in the Character class which does the same thing.


Thank you! I did not know that char are not like String)))
 
Campbell Ritchie
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You’re welcome
 
Don't get me started about those stupid light bulbs.
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