A.int fun(int x){......}B.extern int fun(int x){......}C.void fun(int x){......}D.static int fun(int x){......}
A.int fun(int x,double y=0){......}B.int fun(int x=0,double y=1.5){......}C.int fun(int x=0,double y){......}D.int fun(int x=0,double y=0){......}
A.enum ABC x =four;B.enum ABC x =1;C.enum ABC x =Two;D.enum ABC x =two;