C3 week 123 task 2

1 files changed, 68 insertions, 0 deletions

diff --git a/challenge-123/luc65r/c3/ch-2.c3 b/challenge-123/luc65r/c3/ch-2.c3
new file mode 100644
index 0000000000..05ee05296f
--- /dev/null
+++ b/challenge-123/luc65r/c3/ch-2.c3
@@ -0,0 +1,68 @@
+import std::io;
+
+extern func float strtof(char* str, char** str_end);
+
+struct Point {
+    float x, y;
+}
+
+func void Point.add(Point *a, Point b) {
+    a.x += b.x;
+    a.y += b.y;
+}
+
+func void Point.sub(Point *a, Point b) {
+    a.x -= b.x;
+    a.y -= b.y;
+}
+
+macro abs(x) {
+    return x < 0 ? -x : x;
+}
+
+const float EPSILON = 0.00001;
+
+macro bool eq(a, b) {
+    return @abs(a - b) < EPSILON;
+}
+
+func bool Point.eq(Point *a, Point b) {
+    return @eq(a.x, b.x) && @eq(a.y, b.y);
+}
+
+func int main(int argc, char** argv) {
+    if (argc != 9) return 1;
+
+    Point[4] pts = void;
+    for (int i; i < 8; i++) {
+        (*(float[8]*)(&pts))[i] = strtof(argv[i + 1], null);
+    }
+
+    Point center;
+    foreach (p : pts) center.add(p);
+    center.x /= 4;
+    center.y /= 4;
+
+    Point[4] v = void;
+    v[0] = pts[0];
+    v[0].sub(center);
+    v[1] = { v[0].x, -v[0].y };
+    v[2] = { -v[0].x, v[0].y };
+    v[3] = { -v[0].x, -v[0].y };
+
+    foreach (&x : v) x.add(center);
+
+    bool square = {|
+        for FOUND: (int i; i < 4; i++) {
+            for (int j; j < 4; j++) {
+                if (v[i].eq(pts[j])) continue FOUND;
+            }
+            return false;
+        }
+        return true;
+    |};
+
+    io::printf("%d\n", square);
+
+    return 0;
+}