Think of it like PTSD can be caused by one life threatening event or perceived life threatening event, whereas c-ptsd denotes developmental injury to the sense of self caused by compounded and compounding traumas in the formative developmental years or long term trauma that one might experience in a "death camp" type situation, or a being kidnapped and raped repeatedly over years, or the equivalent.
Developmental trauma can have many adverse symptoms and person and soul injurying effects, personality disorders, chronic dissociative, (mal) adaptive, coping mechanisms, attachment disorders, developmental delays and more.
c-ptsd is just one diagnosis someone who has endured such long term damage could be given, and usually involves trauma re enactment type relational patterns, can include eating disorders, chronic immune system issues, chronic digestive system issues, nervous system inflammation, drug and alcohol issues, the inability to discern and build healthy, as opposed to not healthy connections with others, self harm patterns of various types, suicidal ideation, depression, chronic anxiety, social phobias and avoidance patterns/ disorders, etc, and (often) involves and/or needs many, many years of intensive therapeutic practise(s) to build healthier, neural/endocrine system responses/pathways and attachments, to overcome the learnt fear-based and insecure relational patterns (with self and others) that are the consequence of such long term lack of safety, violation(s) and life and health destroying stress overload(s).