getrandmax Syntax int getrandmaxvoid Description The getrandmax function returns the maximum value that can be returned by a call to rand.. hexdec Syntax int hexdecstring hex_string
Trang 1getrandmax()
Syntax
int getrandmax(void)
Description
The getrandmax() function returns the maximum value that can be returned by a call to rand()
hexdec()
Syntax
int hexdec(string hex_string)
Description
The hexdec() function returns the decimal equivalent of the hexadecimal number represented by hex_string The largest number that can be converted is 7fffffff in
hex, which equates to 2,147,483,647 in decimal
log()
Syntax
float log(float arg)
Description
The log() function returns the natural log of arg
echo log(2.718);//returns ~ 1
log10()
Trang 2Syntax
float log10(float arg)
Description
The log10() function returns the base 10 logarithm of arg
echo log10(100);//returns 2
max()
Syntax
mixed max(mixed arg1, mixed arg2, mixed argn)
Description
The max() function examines the parameter list and returns the numerically highest parameter If arg1 is an array, the highest value in the array will be returned
If arg1 is an integer, string, or double, you need at least two parameters, and max()
returns the largest of these values You can compare an unlimited number of values
If one or more of the parameters are of type double, all the parameters will be treated as doubles, and the return value will be a double If none of the parameters
is a double, they all will be treated as integers, and the return value will be an integer
min()
Syntax
mixed min(mixed arg1, mixed arg2, mixed argn)
Description
The min() function examines the parameter list and returns the numerically lowest parameter If arg1 is an array, the lowest value in the array will be returned
If arg1 is an integer, string, or double, you need at least two parameters and min()
returns the smallest of these values You can compare an unlimited number of values
Trang 3If one or more of the parameters are of type double, all the parameters will be treated as doubles, and the value returned will be a double If none of the parameters is of type double, they all will be treated as integers, and the value returned will be an integer
mt_rand()
Syntax
int mt_rand( [int min] , [int max] )
Description
The mt_rand() function, which was added in PHP 3.0.6 and PHP 4.0, returns a random number utilizing the Mersenne Twister method for generating random numbers instead of the standard libc library The optional parameters of min and
max specify a range you want the random number to fall between (range is
inclusive) Note that you should provide a seed before utilizing any random number functions
For more information, check out http://www.math.keio.ac.jp/~matumoto/emt.html The source for MT is available at http://www.scp.syr.edu/~marc/hawk/twister.html
mt_srand()
Syntax
void mt_srand(int seed)
Description
The mt_srand() function, which was added in PHP 3.0.6 and PHP 4.0, seeds the random number generator with seed This allows the random number generating
functions to produce varying results depending on what seed is given
mt_getrandmax()
Syntax
int mt_getrandmax(void )
Description
Trang 4The mt_getrandmax() function, which was added in PHP 3.0.6 and PHP 4.0, returns the maximum value that can be returned by a call to mt_rand()
number_format()
Syntax
string number_format(float number, int decimals, string dec_point,
string thousands_sep)
Description
The number_format() function returns a formatted version of number based on the
formatting information supplied in the other parameters If only one parameter is given, number will be formatted with a comma as the thousands separator character
Two parameters indicate that the number should be formatted with the parameter
decimals number of decimal places after the decimal point Also, a comma will be
used as the thousands separator character
Four parameters indicate that number should be formatted with the parameter
decimals number of decimal places Also, dec_point indicates the character that
should be used in the decimal point location, namely the separator between the ones and tenths positions Finally, the thousands_sep indicates which character should be
used to indicate a group of thousands In the United States, the decimal point is typically specified as " . " and the thousands separator is specified as " , ", but in some countries these are reversed
octdec()
Syntax
int octdec(string octal_string)
Description
The octdec() function returns the decimal equivalent of octal_string , which
represents an octal number The largest number that can be converted is
17777777777 octal or 2,147,483,647 in decimal
pi()
Syntax
Trang 5double pi(void )
Description
The pi() function returns an approximate value of pi
pow()
Syntax
float pow(float base, float exp)
Description
The pow() function returns the base raised to the power of exp
echo pow(2,3);//returns 8
rad2deg()
Syntax
double rad2deg(double number)
Description
The rad2deg() function , which was added in PHP 3.0.4 and PHP 4.0, takes a number specified in radians and returns its value in degrees
echo rad2deg(pi());//displays 180
rand()
Syntax
int rand ([int min [, int max]])