Random number generator (device): Difference between revisions

Content added Content deleted
(Added Mathematica)
(→‎{{header|C}}: The first example now makes fewer assumptions about the host environment (a uint32_t isn't required for this code to work). Additionally, this code compiles as C89 and returns EXIT_FAILURE instead of 1.)
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It works on systems having /dev/urandom, like [[GNU]]/[[Linux]].
It works on systems having /dev/urandom, like [[GNU]]/[[Linux]].


<lang c>#include <inttypes.h>
<lang c>#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>


#define RANDOM_PATH "/dev/urandom"
int main(int argc, char **argv)
⚫
{
uint32_t v;
FILE *r = fopen("/dev/urandom", "r");
if (r == NULL)
⚫
{
perror("/dev/urandom");
⚫
return 1;
⚫
}


int main(void)
size_t br = fread(&v, sizeof v, 1, r);
⚫
{
if (br < 1)
unsigned char buf[4];
{
unsigned long v;
fputs("/dev/urandom: Not enough bytes\n", stderr);
FILE *fin;
return 1;
}


if ((fin = fopen(RANDOM_PATH, "r")) == NULL) {
⚫
printf("%" PRIu32 "\n", v);
fprintf(stderr, "%s: unable to open file\n", RANDOM_PATH);
⚫
fclose(r);
return 0;
return EXIT_FAILURE;
⚫
}
if (fread(buf, 1, sizeof buf, fin) != sizeof buf) {
fprintf(stderr, "%s: not enough bytes (expected %u)\n",
RANDOM_PATH, (unsigned) sizeof buf);
return EXIT_FAILURE;
⚫
}
⚫
fclose(fin);
v = buf[0] | buf[1] << 8UL | buf[2] << 16UL | buf[3] << 24UL;
⚫
printf("%lu\n", v);
⚫
return 0;
}</lang>
}</lang>


Retrieved from "https://rosettacode.org/wiki/Random_number_generator_(device)"