View Compilation Error

0_0_21950371_31759.cpp:12:1: error: expected ',' or ';' before '{' token
 {
 ^
0_0_21950371_31759.cpp: In function 'int main()':
0_0_21950371_31759.cpp:26:16: error: 'fun' cannot be used as a function
   int r = fun(n);
                ^