Boolean as argument

#1

In add edge function
void addedge(int u, int v , bool bider=true);
why bider is assigned true value?
it should be
void addedge(int u, int v , bool bider);

#2

Assiging the bidirec to true , it just means that if there is bidirec given as argument then it will take the argument otherwise it will assume that the given edge is bidrec