random.h File Reference

#include <stdbool.h>

Go to the source code of this file.

Functions
void	rand_seed (int seed)
void	rand_seed_rand ()
bool	rand_weighted_bool (double percent)
bool	rand_bool ()
int	rand_int ()
double	rand_double ()
double	rand_double_range (double min, double max)
int	rand_int_range (int min, int max)
double	rand_power (double min, double max, double power)
double	rand_gauss (double min, double max, int gauss)
void	rand_string (char *str, int length)
void	rand_string_lower (char *str, int length)
void	rand_string_upper (char *str, int length)
void	rand_string_alpha (char *str, int length)

Function Documentation

rand_bool()

bool rand_bool

(

)

Returns a random boolean.

Returns

double

Examples

bool b = rand_bool(); // b has a 50% chance of being true.

rand_double()

double rand_double

(

)

Returns a random double from 0 to 1.

Returns

double

Examples

double n = rand_double();

rand_double_range()

double rand_double_range	(	double	min,
		double	max
	)

Returns a double between a min and max value.

Parameters

double	min The minimum value of the range.
double	max The maximum value of the range.

Returns

double

Examples

double n = rand_double_range(50, 100);

rand_gauss()

double rand_gauss	(	double	min,
		double	max,
		int	gauss
	)

Returns a double within a range, weighted with a bell curve towards the center of the range.

The gauss parameter affects the strength of the bell curve. The higher gauss is set, the more likely the return values will tend towards the center of the range. A gauss of 1 makes this function work exactly like rand_double_range.

Parameters

double	min The minimum value of the range.
double	max The maximum value of the range.
double	gauss The strength of the bell curve.

Returns

double

Examples

double n = rand_gauss(0, 100, 2); // n will be more somewhat more likely to be closer to 50 than a random range.
double m = rand_gauss(0, 100, 10); // m will be very much more likely to be closer to 50.

rand_int()

int rand_int

(

)

Returns a random integer from 0 to MAX_RAND.

Returns

int

Examples

int n = rand_int();

rand_int_range()

int rand_int_range	(	int	min,
		int	max
	)

Returns a int between a min and max value.

Parameters

int	min The minimum value of the range.
int	max The maximum value of the range.

Returns

int

Examples

int n = rand_int_range(50, 100);

rand_power()

double rand_power	(	double	min,
		double	max,
		double	power
	)

Returns a double within a range, weighted exponentially towards one end of the range.

The power parameter affects where the return value will end up. A power value of one makes this function work exactly like rand_double_range. As the power value decreases towards zero, the return values will tend towards maximum, and as power increases above 1, the return values will tend towards minimum.

Parameters

double	min The minimum value of the range.
double	max The maximum value of the range.
double	power The power of the exponent that affects the result.

Returns

double

Examples

double n = rand_power(0, 100, 2); // n will be more likely to be closer to 0.
double m = rand_power(0, 100, 0.2); // m will be more likely to be closer to 100.

rand_seed()

void rand_seed

(

int

seed

)

Sets the seed used for generating random values.

Calling the same series of rand functions after setting the seed to the same value will result in the same series of random results.

Parameters

int	seed The seed value.

Examples

rand_seed(0);
double a = rand_double();
int b = rand_int();

rand_seed(0);
double c = rand_double(); // c will equal a
int d = rand_int(); // d will equal b

rand_seed_rand()

void rand_seed_rand

(

)

Sets the seed used for generating random values.

This actually sets the seed using a couple of different time functions designed to give a fairly decent random seed.

Examples

rand_seed_rand();
int b = rand_int(); // who knows what b will equal?

rand_string()

void rand_string	(	char *	str,
		int	length
	)

Creates a random string which may contain upper and lower case characters, digits and other ascii symbols.

The char array that is passed in should have a length of at least length + 1 to account for the null terminator.

Parameters

char	*str A char array that will receive the random string.
int	length The length of the string returned.

Returns

char*

Examples

char str[11];
rand_string(str, 10);
printf("str: %s\n", str);

rand_string_alpha()

void rand_string_alpha	(	char *	str,
		int	length
	)

Creates a random string of upper and lower case letters.

The char array that is passed in should have a length of at least length + 1 to account for the null terminator.

Parameters

char	*str A char array that will receive the random string.
int	length The length of the string returned.

Returns

char*

Examples

char str[11];
rand_string_alpha(str, 10);
printf("str: %s\n", str);

rand_string_lower()

void rand_string_lower	(	char *	str,
		int	length
	)

Creates a random string of lower case letters. The char array that is passed in should have a length of at least length + 1 to account for the null terminator.

Parameters

char	*str A char array that will receive the random string.
int	length The length of the string returned.

Returns

char*

Examples

char str[11];
rand_string_lower(str, 10);
printf("str: %s\n", str);

rand_string_upper()

void rand_string_upper	(	char *	str,
		int	length
	)

Creates a random string of upper case letters.

The char array that is passed in should have a length of at least length + 1 to account for the null terminator.

Parameters

char	*str A char array that will receive the random string.
int	length The length of the string returned.

Returns

char*

Examples

char str[11];
rand_string_upper(str, 10);
printf("str: %s\n", str);

rand_weighted_bool()

bool rand_weighted_bool

(

double

percent

)

Returns a random boolean. Allows you to weight the odds of getting true or false.

Parameters

double

percent The odds of getting true. 0 it 0%. 0.5 is 50%. 1.0 is 100%.

Returns

double

Examples

bool b = rand_weighted_bool(0.2); // b has a 20% chance of being true.