运行 ID: 21074

Main.cc:3:5: error: cannot declare ‘::main’ to be a global variable
 int main{
     ^~~~
Main.cc:4:2: error: expected primary-expression before ‘int’
  int n,a,k;
  ^~~
Main.cc:4:2: error: expected ‘}’ before ‘int’
Main.cc:5:2: error: ‘cin’ does not name a type; did you mean ‘sin’?
  cin>>n;
  ^~~
  sin
Main.cc:6:2: error: expected unqualified-id before ‘for’
  for(int i=n-1;i>=1;i--){
  ^~~
Main.cc:6:16: error: ‘i’ does not name a type
  for(int i=n-1;i>=1;i--){
                ^
Main.cc:6:21: error: ‘i’ does not name a type
  for(int i=n-1;i>=1;i--){
                     ^
Main.cc:12:2: error: expected unqualified-id before ‘for’
  for(int i=1;i<=n;i++){
  ^~~
Main.cc:12:14: error: ‘i’ does not name a type
  for(int i=1;i<=n;i++){
              ^
Main.cc:12:19: error: ‘i’ does not name a type
  for(int i=1;i<=n;i++){
                   ^
Main.cc:18:2: error: expected unqualified-id before ‘return’
  return 0;
  ^~~~~~
Main.cc:19:1: error: expected declaration before ‘}’ token
 }
 ^