see #1: concepts demo

code/10/10.1.without.concepts.cpp

@@ -0,0 +1,8 @@
+#include <list>
+#include <algorithm>
+
+int main() {
+    std::list<int> l = {1, 2, 3};
+    // std::sort(l.begin(), l.end()); // tons of compile error
+    return 0;
+}