CODEWITHSUNDEEP
cfloating-pointprintf
user3677241
user3677241

Reputation: 11

Floating point formatting till specified number

The following is a sample prog

#include<stdio.h>
#include<math.h>
main()
{
        int x;
        scanf("%d",&x);
        printf("%.2f\n",(1/pow(2,x)));
}

Here I give .2f for floating point formatting. We can also give respective .3f or .5f etc according to requirement.

Suppose we do not know till what decimal after the '.' it is to be printed. I want to give something like a value n through input, so that it prints decimals till the n.

like .nf if n = 5 and x =1, it prints 0.50000 and for n = 3 it should print 0.500

How do I achieve this?

Upvotes: 0

Views: 77

Answers (1)

devnull
devnull

Reputation: 123448

You can specify the desired precision as a variable:

int n = 5;
printf("%.*f\n", n, (1.0/pow(2,x)));   /* equivalent to %.5f */

Quoting from man 3 printf:

   An  optional  precision,  in the form of a period ('.')  followed by an
   optional decimal digit string.  Instead of a decimal digit  string  one
   may write "*" or "*m$" (for some decimal integer m) to specify that the
   precision is given in the next  argument,  or  in  the  m-th  argument,
   respectively,  which must be of type int.

Upvotes: 8

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