14进制数该怎么输入？
有个题目“如何把某一个k进制的数化为10进制数？”，如果是11进制到15进制的数该怎么输入？
[解决办法]
strtoul, wcstoul
Convert strings to an unsigned long-integer value.
unsigned long strtoul( const char *nptr, char **endptr, int base );
unsigned long wcstoul( const wchar_t *nptr, wchar_t **endptr, int base );
Routine Required Header Compatibility
strtoul <stdlib.h> ANSI, Win 95, Win NT
wcstoul <stdlib.h> or <wchar.h> ANSI, Win 95, Win NT
For additional compatibility information, see Compatibility in the Introduction.
Libraries
LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version
Return Value
strtoul returns the converted value, if any, or ULONG_MAX on overflow. strtoul returns 0 if no conversion can be performed. wcstoul returns values analogously to strtoul. For both functions, errno is set to ERANGE if overflow or underflow occurs.
Parameters
nptr
Null-terminated string to convert
endptr
Pointer to character that stops scan
base
Number base to use
Remarks
Each of these functions converts the input string nptr to an unsigned long.
strtoul stops reading the string nptr at the first character it cannot recognize as part of a number. This may be the terminating null character, or it may be the first numeric character greater than or equal to base. The LC_NUMERIC category setting of the current locale determines recognition of the radix character in nptr; for more information, see setlocale. If endptr is not NULL, a pointer to the character that stopped the scan is stored at the location pointed to by endptr. If no conversion can be performed (no valid digits were found or an invalid base was specified), the value of nptr is stored at the location pointed to by endptr.
wcstoul is a wide-character version of strtoul; its nptr argument is a wide-character string. Otherwise these functions behave identically.
Generic-Text Routine Mappings
TCHAR.H Routine _UNICODE & _MBCS Not Defined _MBCS Defined _UNICODE Defined
_tcstoul strtoul strtoul wcstoul
strtoul expects nptr to point to a string of the following form:
[whitespace] [{+
[解决办法]
–}] [0 [{ x
[解决办法]
X }]] [digits]
A whitespace may consist of space and tab characters, which are ignored; digits are one or more decimal digits. The first character that does not fit this form stops the scan. If base is between 2 and 36, then it is used as the base of the number. If base is 0, the initial characters of the string pointed to by nptr are used to determine the base. If the first character is 0 and the second character is not 'x' or 'X', the string is interpreted as an octal integer; otherwise, it is interpreted as a decimal number. If the first character is '0' and the second character is 'x' or 'X', the string is interpreted as a hexadecimal integer. If the first character is '1' through '9', the string is interpreted as a decimal integer. The letters 'a' through 'z' (or 'A' through 'Z') are assigned the values 10 through 35; only letters whose assigned values are less than base are permitted. strtoul allows a plus (+) or minus (–) sign prefix; a leading minus sign indicates that the return value is negated.
Example
/* STRTOD.C: This program uses strtod to convert a
* string to a double-precision value; strtol to
* convert a string to long integer values; and strtoul
* to convert a string to unsigned long-integer values.
*/
#include <stdlib.h>
#include <stdio.h>
void main( void )
{
char *string, *stopstring;
double x;
long l;
int base;
unsigned long ul;
string = "3.1415926This stopped it";
x = strtod( string, &stopstring );
printf( "string = %s\n", string );
printf(" strtod = %f\n", x );
printf(" Stopped scan at: %s\n\n", stopstring );
string = "-10110134932This stopped it";
l = strtol( string, &stopstring, 10 );
printf( "string = %s", string );
printf(" strtol = %ld", l );
printf(" Stopped scan at: %s", stopstring );
string = "10110134932";
printf( "string = %s\n", string );
/* Convert string using base 2, 4, and 8: */
for( base = 2; base <= 8; base *= 2 )
{
/* Convert the string: */
ul = strtoul( string, &stopstring, base );
printf( " strtol = %ld (base %d)\n", ul, base );
printf( " Stopped scan at: %s\n", stopstring );
}
}
Output
string = 3.1415926This stopped it
strtod = 3.141593
Stopped scan at: This stopped it
string = -10110134932This stopped it strtol = -2147483647 Stopped scan at: This stopped itstring = 10110134932
strtol = 45 (base 2)
Stopped scan at: 34932
strtol = 4423 (base 4)
Stopped scan at: 4932
strtol = 2134108 (base 8)
Stopped scan at: 932
Data Conversion Routines, Locale Routines
[解决办法]
strtod Functions Overview
See Also strtod, strtol, atof, localeconv, setlocale
