feat: add quiz 3 cross-checker.

cross-checker/main.cpp

@@ -0,0 +1,24 @@
+#include <cross-checker.h>
+#include <iostream>
+
+int main(int argc, char** argv)
+{
+    if (argc != 9)
+    {
+        std::cout << "ERROR: 4 point must be provided" << std::endl;
+    }
+
+    cross_checker::Line line1(cross_checker::Point(std::stod(argv[1]), std::stod(argv[2])), cross_checker::Point(
+                                  std::stod(argv[3]), std::stod(argv[4])));
+    cross_checker::Line line2(cross_checker::Point(std::stod(argv[5]), std::stod(argv[6])), cross_checker::Point(
+                                  std::stod(argv[7]), std::stod(argv[8])));
+
+    if (line1.intersect(line2))
+    {
+        std::cout << "TRUE" << std::endl;
+    }
+    else
+    {
+        std::cout << "FALSE" << std::endl;
+    }
+}