Этот подход использует стек вместо кучи памяти, поэтому он должен быть быстрее.
Цель - быстрый код, небольшой размер и ОЧЕНЬ БОЛЬШИЕ значения не имеют значения.
Только в очень редких случаях закругления углов необходимы дополнительные циклы ЦП.
Это также позволяет комбинировать с другими форматами и значениями в дальнейшем printf().
NEW: дополнительное решение для формата: h:mm:ss.nnnnnn
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <math.h>
#define MAX_BUF_SZ 32
#ifndef DBL_MAX
#define DBL_MAX 1.7976931348623157e+308
#endif
static char *minutes_str(char *buf, double time) {
const char *format = (time >= 0 ? "%d:%09.6f" : "-%d:%09.6f");
time = (fabs(time) > INT_MAX * 60.0 ? INT_MAX * 60.0 : fabs(time));
int len = snprintf(buf, MAX_BUF_SZ, format, (int)(time / 60), fmod(time, 60));
if (len - 9 >= 0 && buf[len - 9] > '5') // correct rare rounding issue
len = snprintf(buf, MAX_BUF_SZ, format, (int)(time / 60) + 1, .0);
while (buf[--len] == '0'); // search trailing zeros or ...
buf[len + (buf[len] != '.')] = '\0'; // dot and strip them
return buf;
}
/**
* Convenience macro. The return value should be used only directly in
* function arguments but never stand-alone.
*/
#define time2minutestr(time) minutes_str((char[MAX_BUF_SZ]){'\0'}, time)
static char *hours_string(char *buf, double time)
{
const char *format = (time >= 0 ? "%d:%02d:%09.6f" : "-%d:%02d:%09.6f");
if (time == (double)NAN)
printf("Invalid number\n");
time = (fabs(time) > INT_MAX * 60.0 * 60.0 ? INT_MAX * 60.0 * 60.0 : fabs(time));
int hours = time / 60 / 60, minutes = fmod(time / 60, 60);
int len = snprintf(buf, MAX_BUF_SZ, format, hours, minutes, fmod(time, 60));
if (len - 9 >= 0 && buf[len - 9] > '5') { // correct rare rounding issue
if (++minutes > 59) {
minutes = 0;
hours++;
}
len = snprintf(buf, MAX_BUF_SZ, format, hours, minutes, .0);
}
while (buf[--len] == '0'); // search trailing zeros or ...
buf[len + (buf[len] != '.')] = '\0'; // dot and strip them
return buf;
}
/**
* Convenience macro. The return value should be used only directly in
* function arguments but never stand-alone.
*/
#define time2hourstr(time) hours_string((char[MAX_BUF_SZ]){'\0'}, time)
int main(int argc, char** argv)
{
double a[] = {
0, -1, 1, 59, 60, 61,
121.1, 121.11, 121.111, 121.1111, 121.11111, 121.111111,
12345.6,
123.456789,
129.9999994,
129.9999995,
599.9999994,
599.9999995,
599.99999951,
599.9999999,
23.9999999999,
999.0000005, 1000.0000005, -999.0000005, -1000.0000005,
999.9999999, -999.9999999,
1e6, 1e12, 1e18,
4321.0, -0.0, 59.9999994, 59.9999996,
INT_MAX * 60.0, INT_MAX * 60.0 + 1234,
-(INT_MAX + 1.0) * 60.0, -(INT_MAX + 1.0) * 60.0 - 1234,
(double)ULLONG_MAX * 64.0, DBL_MAX, 1.0 / 0.0, (double)NAN,
};
size_t i;
for (i = 0; i < sizeof(a) / sizeof(a[0]); i++) {
printf("%32.16g", a[i]);
printf(" --> %s %s\n", time2minutestr(a[i]), "some text");
printf("%32.16g", -a[i]);
printf(" --> %s %s\n", time2minutestr(-a[i]), "some text");
}
printf(" H A P P Y !\n");
double b[] = {
0, -1, 1, 59, 60, 61,
12345.6,
123.456789,
3609.9999995,
3609.99999951,
359999.9999994,
359999.9999995,
359999.99999951,
719999.9999995, 7199.9999999999,
1e6, 1e12, 1e18,
INT_MAX * 60.0, INT_MAX * 60.0 * 60.0,
-(INT_MAX + 1.0) * 60.0, -(INT_MAX + 1.0) * 60.0 * 60.0,
(double)ULLONG_MAX * 64.0, DBL_MAX, 1.0 / 0.0, (double)NAN,
};
for (i = 0; i < sizeof(b) / sizeof(b[0]); i++) {
printf("%32.16g", b[i]);
printf(" --> %s %s\n", time2hourstr(b[i]), "some other text");
printf("%32.16g", -b[i]);
printf(" --> %s %s\n", time2hourstr(-b[i]), "some other text");
}
printf(" V E R Y H A P P Y !\n");
return (0);
}
Выход:
0 --> 0:00 some text
-0 --> 0:00 some text
-1 --> -0:01 some text
1 --> 0:01 some text
1 --> 0:01 some text
-1 --> -0:01 some text
59 --> 0:59 some text
-59 --> -0:59 some text
60 --> 1:00 some text
-60 --> -1:00 some text
61 --> 1:01 some text
-61 --> -1:01 some text
121.1 --> 2:01.1 some text
-121.1 --> -2:01.1 some text
121.11 --> 2:01.11 some text
-121.11 --> -2:01.11 some text
121.111 --> 2:01.111 some text
-121.111 --> -2:01.111 some text
121.1111 --> 2:01.1111 some text
-121.1111 --> -2:01.1111 some text
121.11111 --> 2:01.11111 some text
-121.11111 --> -2:01.11111 some text
121.111111 --> 2:01.111111 some text
-121.111111 --> -2:01.111111 some text
12345.6 --> 205:45.6 some text
-12345.6 --> -205:45.6 some text
123.456789 --> 2:03.456789 some text
-123.456789 --> -2:03.456789 some text
129.9999994 --> 2:09.999999 some text
-129.9999994 --> -2:09.999999 some text
129.9999995 --> 2:10 some text
-129.9999995 --> -2:10 some text
599.9999994 --> 9:59.999999 some text
-599.9999994 --> -9:59.999999 some text
599.9999994999999 --> 9:59.999999 some text
-599.9999994999999 --> -9:59.999999 some text
599.99999951 --> 10:00 some text
-599.99999951 --> -10:00 some text
599.9999999 --> 10:00 some text
-599.9999999 --> -10:00 some text
23.9999999999 --> 0:24 some text
-23.9999999999 --> -0:24 some text
999.0000005000001 --> 16:39.000001 some text
-999.0000005000001 --> -16:39.000001 some text
1000.0000005 --> 16:40.000001 some text
-1000.0000005 --> -16:40.000001 some text
-999.0000005000001 --> -16:39.000001 some text
999.0000005000001 --> 16:39.000001 some text
-1000.0000005 --> -16:40.000001 some text
1000.0000005 --> 16:40.000001 some text
999.9999999 --> 16:40 some text
-999.9999999 --> -16:40 some text
-999.9999999 --> -16:40 some text
999.9999999 --> 16:40 some text
1000000 --> 16666:40 some text
-1000000 --> -16666:40 some text
1000000000000 --> 2147483647:00 some text
-1000000000000 --> -2147483647:00 some text
1e+18 --> 2147483647:00 some text
-1e+18 --> -2147483647:00 some text
4321 --> 72:01 some text
-4321 --> -72:01 some text
-0 --> 0:00 some text
0 --> 0:00 some text
59.9999994 --> 0:59.999999 some text
-59.9999994 --> -0:59.999999 some text
59.9999996 --> 1:00 some text
-59.9999996 --> -1:00 some text
128849018820 --> 2147483647:00 some text
-128849018820 --> -2147483647:00 some text
128849020054 --> 2147483647:00 some text
-128849020054 --> -2147483647:00 some text
-128849018880 --> -2147483647:00 some text
128849018880 --> 2147483647:00 some text
-128849020114 --> -2147483647:00 some text
128849020114 --> 2147483647:00 some text
1.180591620717411e+21 --> 2147483647:00 some text
-1.180591620717411e+21 --> -2147483647:00 some text
1.797693134862316e+308 --> 2147483647:00 some text
-1.797693134862316e+308 --> -2147483647:00 some text
inf --> 2147483647:00 some text
-inf --> -2147483647:00 some text
nan --> --2147483648: nan some text
-nan --> --2147483648: nan some text
H A P P Y !
0 --> 0:00:00 some other text
-0 --> 0:00:00 some other text
-1 --> -0:00:01 some other text
1 --> 0:00:01 some other text
1 --> 0:00:01 some other text
-1 --> -0:00:01 some other text
59 --> 0:00:59 some other text
-59 --> -0:00:59 some other text
60 --> 0:01:00 some other text
-60 --> -0:01:00 some other text
61 --> 0:01:01 some other text
-61 --> -0:01:01 some other text
12345.6 --> 3:25:45.6 some other text
-12345.6 --> -3:25:45.6 some other text
123.456789 --> 0:02:03.456789 some other text
-123.456789 --> -0:02:03.456789 some other text
3609.9999995 --> 1:00:09.999999 some other text
-3609.9999995 --> -1:00:09.999999 some other text
3609.99999951 --> 1:00:10 some other text
-3609.99999951 --> -1:00:10 some other text
359999.9999994 --> 99:59:59.999999 some other text
-359999.9999994 --> -99:59:59.999999 some other text
359999.9999995 --> 99:59:59.999999 some other text
-359999.9999995 --> -99:59:59.999999 some other text
359999.99999951 --> 100:00:00 some other text
-359999.99999951 --> -100:00:00 some other text
719999.9999995 --> 199:59:59.999999 some other text
-719999.9999995 --> -199:59:59.999999 some other text
7199.9999999999 --> 2:00:00 some other text
-7199.9999999999 --> -2:00:00 some other text
1000000 --> 277:46:40 some other text
-1000000 --> -277:46:40 some other text
1000000000000 --> 277777777:46:40 some other text
-1000000000000 --> -277777777:46:40 some other text
1e+18 --> 2147483647:00:00 some other text
-1e+18 --> -2147483647:00:00 some other text
128849018820 --> 35791394:07:00 some other text
-128849018820 --> -35791394:07:00 some other text
7730941129200 --> 2147483647:00:00 some other text
-7730941129200 --> -2147483647:00:00 some other text
-128849018880 --> -35791394:08:00 some other text
128849018880 --> 35791394:08:00 some other text
-7730941132800 --> -2147483647:00:00 some other text
7730941132800 --> 2147483647:00:00 some other text
1.180591620717411e+21 --> 2147483647:00:00 some other text
-1.180591620717411e+21 --> -2147483647:00:00 some other text
1.797693134862316e+308 --> 2147483647:00:00 some other text
-1.797693134862316e+308 --> -2147483647:00:00 some other text
inf --> 2147483647:00:00 some other text
-inf --> -2147483647:00:00 some other text
nan --> --2147483648:-2147483648: some other text
-nan --> --2147483648:-2147483648: some other text
V E R Y H A P P Y !