There are 54 African countries. Of these 9 countries experienced wars of independence or major uprisings against the colonial authorities. There are a further 3 highly convoluted cases (Congo, Rwanda, Zimbabwe) where the process of becoming independent involved serious violence - although there was no war of independence or major uprising against the colonial authorities. That means 42 countries - 78 percent of African nations - transitioned peacefully to independence.

No, quite a few countries gained independence without anything near Vietnam or WWII.