1 files changed, 53 insertions, 0 deletions
diff --git a/misc/examples/algo/generator.c b/misc/examples/algo/generator.c
new file mode 100644
index 00000000..fce44a52
--- /dev/null
+++ b/misc/examples/algo/generator.c
@@ -0,0 +1,53 @@
+// https://quuxplusone.github.io/blog/2019/03/06/pythagorean-triples/
+
+#include <stc/algo/coroutine.h>
+#include <stdio.h>
+
+typedef struct {
+    int n;
+    int a, b, c;
+} Triple_value, Triple;
+
+typedef struct {
+    Triple_value* ref;
+    int cco_state;
+} Triple_iter;
+
+bool Triple_next(Triple_iter* it) {
+    Triple_value* t = it->ref;
+    cco_begin(it);
+        for (t->c = 1;; ++t->c) {
+            for (t->a = 1; t->a < t->c; ++t->a) {
+                for (t->b = t->a; t->b < t->c; ++t->b) {
+                    if (t->a*t->a + t->b*t->b == t->c*t->c) {
+                        cco_yield(true);
+                        if (t->n-- == 1) cco_return;
+                    }
+                }
+            }
+        }
+        cco_final:
+            it->ref = NULL;
+    cco_end(false);
+}
+
+Triple_iter Triple_begin(Triple* t) {
+    Triple_iter it = {t}; 
+    if (t->n > 0) Triple_next(&it);
+    else it.ref = NULL;
+    return it;
+}
+
+
+int main()
+{
+    puts("Pythagorean triples with c < 100:");
+    Triple t = {INT32_MAX};
+    c_foreach (i, Triple, t)
+    {
+        if (i.ref->c < 100)
+            printf("%u: (%d, %d, %d)\n", INT32_MAX - i.ref->n + 1, i.ref->a, i.ref->b, i.ref->c);
+        else
+            (void)cco_stop(&i);
+    }
+}