CODEWITHSUNDEEP
objective-c
Balu
Balu

Reputation: 1

How to get float value as it is from the text box in objective c

Can any one please help me how to get float value as it is from text box

for Ex: I have entered 40.7 

rateField=[[rateField text] floatValue];

I am getting rateField value as 40.7000008 but I want 40.7 only.

please help me.

thanks in advance

Thanks Every body,

I tried all the possibilities but I am not able to get what I want. I am not looking to print the value to convert into string.I want to use that value for computation. If i use Number Formatter again when i am converting from number to float it is giving same problem.So i want float value only but it should be whatever i have given in the text box it should not be padded with any values.This is my requirement.Please help me.

thanks&regards Balu

Thanks Every body,

I tried all the possibilities but I am not able to get what I want. I am not looking to print the value to convert into string.I want to use that value for computation. If i use Number Formatter again when i am converting from number to float it is giving same problem.So i want float value only but it should be whatever i have given in the text box it should not be padded with any values.This is my requirement.Please help me.

thanks&regards Balu

Upvotes: 0

Views: 887

Answers (4)

tt.Kilew
tt.Kilew

Reputation: 6084

You are already resolved float value.

Floating point numbers have limited precision. Although it depends on the system, float relative error due to rounding will be around 1.1e-8 Non elementary arithmetic operations may give larger errors, and, of course, error progragation must be considered when several operations are compounded.

Additionally, rational numbers that are exactly representable as floating point numbers in base 10, like 0.1 or 0.7, do not have an exact representation as floating point numbers in base 2, which is used internally, no matter the size of the mantissa. Hence, they cannot be converted into their internal binary counterparts without a small loss of precision. This can lead to confusing results: for example, floor((0.1+0.7)*10) will usually return 7 instead of the expected 8, since the internal representation will be something like 7.9999999999999991118....

So if you're using those numbers for output, you should use some rounding mechanism, even for double values.

Upvotes: 0

Alan Donsky
Alan Donsky

Reputation: 31

When using floating point numbers, these things can happen because of the way the numbers are stored in binary format in the computers memory.

It's similar to the way 1/3 = 0.33333333333333... in decimal numbers.

The best way to deal with this is to use number formatters in the textbox that displays the value.

Upvotes: 0

Nekto
Nekto

Reputation: 17877

This is ok. There is not guaranteed that you will get 40.7 if you will use even double.

If you want to output 40.7 you can use %.1f or NSNumberFormatter

Upvotes: 3

nekno
nekno

Reputation: 19267

Try using a double instead. Usually solves that issue. Has to do with the storage precision.

double dbl = [rateField.text doubleValue];

Upvotes: 0

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