运行 ID: 3655

Main.cc: In function ‘int main()’:
Main.cc:5:7: error: ‘n’ was not declared in this scope
  cin>>n;
       ^
Main.cc:7:12: error: expected ‘;’ before ‘<=’ token
   for(int j<=n;j++){
            ^~
Main.cc:7:12: error: expected primary-expression before ‘<=’ token
Main.cc:9:23: error: ‘sum’ was not declared in this scope
    if(i+j==n+1||i==j) sum+=a[i][j];
                       ^~~
Main.cc:12:8: error: ‘sum’ was not declared in this scope
  cout<