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| author | Tyge Løvset <[email protected]> | 2021-01-21 08:26:54 +0100 |
|---|---|---|
| committer | Tyge Løvset <[email protected]> | 2021-01-21 08:26:54 +0100 |
| commit | 50da396d04714a18fa087ebbd1f2316958dbd6bd (patch) | |
| tree | 0349909bf35183e2eced05ca0d3ce909f700c23e /examples/cbits_prime.c | |
| parent | 9473eae780011ef520066ddcd36bb555e8e616e4 (diff) | |
| download | STC-modified-50da396d04714a18fa087ebbd1f2316958dbd6bd.tar.gz STC-modified-50da396d04714a18fa087ebbd1f2316958dbd6bd.zip | |
Reverted namings: crand to crandom, and copt to coption.
Diffstat (limited to 'examples/cbits_prime.c')
| -rw-r--r-- | examples/cbits_prime.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/examples/cbits_prime.c b/examples/cbits_prime.c new file mode 100644 index 00000000..5c5d3969 --- /dev/null +++ b/examples/cbits_prime.c @@ -0,0 +1,39 @@ +#include <stdio.h>
+#include <stc/cbits.h>
+
+static inline cbits sieveOfEratosthenes(size_t n)
+{
+ cbits primes = cbits_with_size(n + 1, true);
+ cbits_reset(&primes, 0);
+ cbits_reset(&primes, 1);
+
+ c_forrange (i, size_t, 2, n+1) {
+ // If primes[i] is not changed, then it is a prime
+ if (cbits_test(primes, i) && i*i <= n) {
+ c_forrange (j, size_t, i*i, n+1, i) {
+ cbits_reset(&primes, j);
+ }
+ }
+ }
+ return primes;
+}
+
+
+int main(void)
+{
+ int n = 100000000;
+ printf("computing prime numbers up to %u\n", n);
+
+ cbits primes = sieveOfEratosthenes(n);
+ puts("done");
+
+ size_t np = cbits_count(primes);
+ printf("number of primes: %zu\n", np);
+
+ printf("2 ");
+ c_forrange (i, int, 3, 1001, 2) {
+ if (cbits_test(primes, i)) printf("%d ", i);
+ }
+ puts("");
+ cbits_del(&primes);
+}
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