68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
/*
|
|
FUNCTION
|
|
<<itoa>>---integer to string
|
|
|
|
INDEX
|
|
itoa
|
|
|
|
SYNOPSIS
|
|
#include <stdlib.h>
|
|
char *itoa(int <[value]>, char *<[str]>, int <[base]>);
|
|
char *__itoa(int <[value]>, char *<[str]>, int <[base]>);
|
|
|
|
DESCRIPTION
|
|
<<itoa>> converts the integer <[value]> to a null-terminated string
|
|
using the specified base, which must be between 2 and 36, inclusive.
|
|
If <[base]> is 10, <[value]> is treated as signed and the string will be
|
|
prefixed with '-' if negative. For all other bases, <[value]> is treated as
|
|
unsigned. <[str]> should be an array long enough to contain the converted
|
|
value, which in the worst case is sizeof(int)*8+1 bytes.
|
|
|
|
RETURNS
|
|
A pointer to the string, <[str]>, or NULL if <[base]> is invalid.
|
|
|
|
PORTABILITY
|
|
<<itoa>> is non-ANSI.
|
|
|
|
No supporting OS subroutine calls are required.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
|
|
char *
|
|
__itoa (int value,
|
|
char *str,
|
|
int base)
|
|
{
|
|
unsigned uvalue;
|
|
int i = 0;
|
|
|
|
/* Check base is supported. */
|
|
if ((base < 2) || (base > 36))
|
|
{
|
|
str[0] = '\0';
|
|
return NULL;
|
|
}
|
|
|
|
/* Negative numbers are only supported for decimal.
|
|
* Cast to unsigned to avoid overflow for maximum negative value. */
|
|
if ((base == 10) && (value < 0))
|
|
{
|
|
str[i++] = '-';
|
|
uvalue = (unsigned)-value;
|
|
}
|
|
else
|
|
uvalue = (unsigned)value;
|
|
|
|
__utoa (uvalue, &str[i], base);
|
|
return str;
|
|
}
|
|
|
|
char *
|
|
itoa (int value,
|
|
char *str,
|
|
int base)
|
|
{
|
|
return __itoa (value, str, base);
|
|
}
|