Arduino error. Can;t find it

I am getting arduino error here.

struct student{
int num,ac,sp,co, sum = 0;
    if (ac>=30 && sp>=30 && co>=30) 
    ^
        sum = ac+sp+co;
};

I am just learning my way around C++ right now, so it can be a stupid mistake.. Thanks in advance. exact error: line:12 col:6 [Error] expected unqualified-id before 'if'