fix starting with default values when no arguments are passed

main.cpp

@@ -58,12 +58,15 @@ int main(int argc, char **argv)
         }
     }
 
-    try {
-        tcount = std::stoi(targ);
-        maxiter = std::stoi(iarg);
-    } catch(...) {
-        std::cout << "Invalid arguments." << std::endl;
-        exit(1);
+
+    if (!targ.empty() && !iarg.empty()) {
+        try {
+            tcount = std::stoi(targ);
+            maxiter = std::stoi(iarg);
+        } catch(...) {
+            std::cout << "Invalid arguments." << std::endl;
+            exit(1);
+        }
     }
 
     if (tcount == 0 || tcount < 0)