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author | Stefan Zabka <zabkaste@hu-berlin.de> | 2020-05-24 12:19:52 +0200 |
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committer | Stefan Zabka <zabkaste@hu-berlin.de> | 2020-05-24 12:19:52 +0200 |
commit | 04576dc2a3f761eb041b808b56f13a58052e7655 (patch) | |
tree | c6bed6db34e29f0dec0c844fbc931b3dd4fab8db /02_exercise/prog.c | |
parent | 65966ded0cc15c5966c6568cf0ff2f2bbe1fc29a (diff) | |
download | betriebssysteme-04576dc2a3f761eb041b808b56f13a58052e7655.tar.gz betriebssysteme-04576dc2a3f761eb041b808b56f13a58052e7655.zip |
Moved back to 02_exercise
Diffstat (limited to '02_exercise/prog.c')
-rw-r--r-- | 02_exercise/prog.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/02_exercise/prog.c b/02_exercise/prog.c new file mode 100644 index 0000000..efd2527 --- /dev/null +++ b/02_exercise/prog.c @@ -0,0 +1,52 @@ +#include <time.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +static unsigned int hash(const void* key, size_t size) { + const char* ptr = key; + unsigned int hval; + + for (hval = 0x811c9dc5u; size --> 0; ++ptr) { + hval ^= *ptr; + hval *= 0x1000193u; + } + + return hval; +} + +static inline int roll(int sides) { + return rand() / (RAND_MAX + 1.0) * sides; +} + +int main(int argc, const char* argv[]) { + int rc, delay; + time_t now = time(0); + + /* initialize the random number generator */ + srand(hash(&now, sizeof(now))); + + /* determine exit code and time delay */ + switch (argc) { + default: + delay = atoi(argv[1]); + rc = atoi(argv[2]); + break; + + case 2: + delay = atoi(argv[1]); + rc = roll(2) - 1; + break; + + case 1: + delay = roll(10); + rc = roll(2) - 1; + break; + } + + printf("Delay: %ds, Exit Code: %d\n", delay, rc); + fflush(stdout); + sleep(delay); + + return rc; +} |