Main.cc:6:5: error: cannot declare '::main' to be a global variable
    6 | int main{
      |     ^~~~
Main.cc:7:5: error: expected primary-expression before 'double'
    7 |     double a;
      |     ^~~~~~
Main.cc:7:5: error: expected '}' before 'double'
Main.cc:6:9: note: to match this '{'
    6 | int main{
      |         ^
Main.cc:9:5: error: 'cin' does not name a type
    9 |     cin >>a>>b>>c;
      |     ^~~
Main.cc:11:5: error: expected unqualified-id before 'for'
   11 |     for(int i = 1 ; i <=b;i++){
      |     ^~~
Main.cc:11:21: error: 'i' does not name a type
   11 |     for(int i = 1 ; i <=b;i++){
      |                     ^
Main.cc:11:27: error: 'i' does not name a type
   11 |     for(int i = 1 ; i <=b;i++){
      |                           ^
Main.cc:15:5: error: 'cout' does not name a type
   15 |     cout << setprecision(10) << sum;
      |     ^~~~
Main.cc:17:1: error: expected declaration before '}' token
   17 | }
      | ^