What's the point of Software Development vs Software development approaches are two separate things.
Software approaches are used in companies, for e.g. if you work for a company that designs game apps for smart phones, agile would be used as they push out several versions (iterations) each iteration improving upon the last iteration based on community input/feedback. The goal being to get the app/game on the market asap.
Structured approach isn't used as much except mainly in large projects that need heavy documentation.
I'm an ex-SDD student lmk if you need any help or notes with the subject, glad to help.