I read somewhere about giving enums default values like so:
typedef enum {
MarketNavigationTypeNone = 0,
MarketNavigationTypeHeirachy = 1,
MarketNavigationTypeM
That are not default values, you are giving them the values they will always have.
If you wouldn't initialize them explicitly, the first enumerators value is zero. For all others, if there is no initializer, their value is the value of the previous enumerator increased by one.
There are two reasons for giving them explicit values:
If you always refer to them by their name and never explicitly use an integral value for comparison or assignment, explicitly giving them a value is not needed.