fixing the readme

lectures/08_vector_implementation/README.md

@@ -124,8 +124,9 @@ v[0] = 13.1; v[2] = 3.14;
 Vec<double> u(v);
 u[2] = 6.5;
 u[3] = -4.8;
-for (unsigned int i=0; i<4; ++i)
-cout << u[i] << " " << v[i] << endl;
+for (unsigned int i=0; i<4; ++i){
+	std::cout << u[i] << " " << v[i] << std::endl;
+}
 ```
 Explain what happens by drawing a picture
 of the memory of both u and v.