---

Lỗi biên dịch:

Main.cc: In function ‘int main()’:
Main.cc:10:20: error: ‘b’ was not declared in this scope
  long long int c=0;b=0
                    ^
Main.cc:14:16: error: ‘a’ was not declared in this scope
         cin >> a[i];
                ^
Main.cc:15:14: error: expected ‘)’ before ‘mod’
         if(i mod 2 !=0){
              ^~~
Main.cc:21:12: error: expected ‘;’ before ‘b’
  else cout b-c; 
            ^
Main.cc:21:15: warning: statement has no effect [-Wunused-value]
  else cout b-c; 
               ^