Best platform for students

I teach C programming in school in Netherland.I got to know studyobject learning courses on google.I was amazed by the course depth they offer. After I finished the course , I told students to take studobject C code challenge , it gives them real insight of problems in industry.Best part is that they also offer quiz after course. Quiz results helps to figure out the competencies of students. My students are getting immensely benefitted by the course.