[Propofol]

Basically, I have a program that deals with a lot of double data type numbers with a variable number of significant figures.

I want to present my user with only the significant figures of a number, so if 6 sig figs were allowed, a number such as 23.4563456 would become 23.4563.

Does anyone know if there is a library function that would allow me to input any number, the number of sig figs, and output the correct value, or will I have to hand-code this?

Thanks!

[Arkham_c]

Originally posted by Propofol:
Basically, I have a program that deals with a lot of double data type numbers with a variable number of significant figures.

I want to present my user with only the significant figures of a number, so if 6 sig figs were allowed, a number such as 23.4563456 would become 23.4563.

Does anyone know if there is a library function that would allow me to input any number, the number of sig figs, and output the correct value, or will I have to hand-code this?

Thanks!

What programming language?

[Propofol]

Sorry!

C, plain, vanilla, ordinary, K&R type.

[Arkham_c]

Originally posted by Propofol:
Sorry!

C, plain, vanilla, ordinary, K&R type.

Do you want to display the number in rounded form, or actually round the number?

[00101001]

... printf() can do this quite easily. let's say you have a float f = 2.33445566. if you do:

printf("%0.2f\n",f);

it will print: 2.33

check out the sprintf variants if you want to store the remaining string.

type:
man printf
into the terminal to see all the nifty things it can do

[chabig]

Couldn't you find a routine to convert it to scientific notation (2.34563456E+1). Then take the mantissa and work on it to get just the number of digits you want (2.34563E+1) and convert the result back to decimal?

[Propofol]

Thanks for the suggestion. I'll work on it using your thoughts.