what to use for calculation operation, help!

[papaboy2]

hi i'm a novice in java and i want to know how can i accurately perform arithmetic operation when i'm using a double variable? becase when i assign a value for example of 100.3 it formats to
100.30000151... somthing, how can accurately use it? thanks! need help pls.


here is my code;
String mysam;
double mydouble;
mysam = CalcNumber.getText()
mydouble = Float.parseFloat(mysam);
System.out.println(mydouble);

 

[sedj]

Do not think you should either use :

double d = Double.parseDouble(string)

or

float f = Float.parseFloat(string)

You are mixing your data types in your example - which I expect is why you are seeing odd results.

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[papaboy2]

but i can't retrieve the value of the textbox and assign it in my double variable, so i used a string variable and convert it to double so that i can perform aritmetic operation, what should i do to get the value of the text field and perform aritmetic operation accurately using double variable?, thanks for replying!

 

[sedj]

Yes, that is fine - mu point is that when you assign the double value from the string, you are using Float.parseFloat() which returns a float, instead of Double.parseDouble() which returns a double. These two primitive data types occupy different amounts of memory - hence your weird results (possibly).

See ?

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[papaboy2]

ok thank you very much! i appreciate it

 

[papaboy2]

i tried the code below but i encounter an error, LastValue is my Double variable and StrFirst is a string variable?

StrFirst = CalcNumber.getText(); LastValue = Double.parseDouble(StrFirst);

 

[sedj]

The error being what exactly ?

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