How to printf a time_t variable as a floating point number?

» c » How to printf a time_t variable as a floating point number?

By : lanjusto

Date : January 10 2021, 01:49 PM

it fixes the issue The resolution of time_t is at most one second on most platforms. That is, on most platforms, time_t will be an integer (32- or 64-bit) value counting the number of seconds elapsed since midnight of Jan 1st 1970 (UTC), and can only achieve one-second resolution.
Therefore, a sum of time_t values will also only exhibit one-second resolution (no decimal part, even after converting to double.)

code :

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How to format the exponent of a floating point number in printf %E (scientific)

By : toxsedyshev

Date : March 29 2020, 07:55 AM

may help you . Ruby's sprintf is just a wrapper around the native libc snprintf. From sprintf.c (Ruby 1.9.2-p180):

code :

/*   
 *  call-seq:
 *     format(format_string [, arguments...] )   -> string
 *     sprintf(format_string [, arguments...] )  -> string 
 * [...]
 */

VALUE
rb_f_sprintf(int argc, const VALUE *argv)
{
    return rb_str_format(argc - 1, argv + 1, GETNTHARG(0));
}

case 'f':
case 'g':
case 'G':
case 'e':
case 'E':
case 'a':
case 'A':
    /* ... */
    snprintf(&buf[blen], need, fbuf, fval);

what's the difference between printf a floating-point variable and constant?

By : Ines de Santiago

Date : March 29 2020, 07:55 AM

To fix the issue you can do The values are different. The first is a float, which is typically 4 bytes. The second is a double, which is typically 8 bytes.
The rules for rounding are based on the third digit after the decimal place. So, in one case, the value is something like 21.19499997 and the other 21.1950000000001, or something like that. (These are made up to illustrate the issue with rounding and imprecise numeric formats.)

How does printf extract digits from a floating point number?

By : Bogor

Date : March 29 2020, 07:55 AM

this will help The classic implementation is David Gay's dtoa. The exact details are somewhat arcane (see Why does "dtoa.c" contain so much code?), but in general it works by doing the base conversion using more precision beyond what you can get from a 32-bit, 64-bit, or even 80-bit floating point number. To do this, it uses so-called "bigints" or arbitrary-precision numbers, which can hold as many digits as you can fit in memory. Gay's code has been copied, with modifications, into countless other libraries including common implementations for the C standard library (so it might power your printf), Java, Python, PHP, JavaScript, etc.
(As a side note... not all of these copies of Gay's dtoa code were kept up to date, so because PHP used an old version of strtod it hung when parsing 2.2250738585072011e-308.)

code :

 * Inspired by "How to Print Floating-Point Numbers Accurately" by
 * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 112-126].

Automatically round floating point number with variable number of zeros after decimal point to first non zero digit

By : Serghei

Date : March 29 2020, 07:55 AM

should help you out I am dealing with floating point numbers and need to display them on an widget on webpage which has limited width. I mostly use tofixed(2) for all my floating point number. But there are certain cases where there are numbers like: 0.0000000365468, only 0.00 are printed because of tofixed(2). I cannot permanently set it to tofixed(8) as normal cases will take too much space then. , You could take the log10 and use a threshold for taking the value.

code :

function f(x) {
    return x.toFixed(Math.log10(x) < -2 ? 8 : 2);
}

console.log(f(0.0000000365468));
console.log(f(0.000000365468));
console.log(f(0.00000365468));
console.log(f(0.0000365468));
console.log(f(0.000365468));
console.log(f(0.00365468));
console.log(f(0.0365468));
console.log(f(12.34));

function f(x) {
    return x.toFixed(Math.max(-Math.log10(x) + 1, 2));
}

console.log(f(0.0000000365468));
console.log(f(0.000000365468));
console.log(f(0.00000365468));
console.log(f(0.0000365468));
console.log(f(0.000365468));
console.log(f(0.00365468));
console.log(f(0.0365468));
console.log(f(12.34));

printf - Wrong answer on a floating point number

By : Fitri Andrianabel Kh

Date : March 29 2020, 07:55 AM

wish help you to fix your issue I'm trying to divide two numbers together and print the answer but the compiler always gives 1.000000 as the answer, Iv'e tried changing the literals but the answer is still the same somewhat. , Change