foo.cpp:1:1: error: 'include' does not name a type
 include <iostream> include <stdio.h>
 ^~~~~~~
foo.cpp: In function 'int main()':
foo.cpp:8:18: error: 'scanf' was not declared in this scope
 scanf( "%d" , &t );
                  ^
foo.cpp:12:1: error: 'cout' was not declared in this scope
 cout << ( n - x ) * x << ".0000" << endl;
 ^~~~
foo.cpp:12:37: error: 'endl' was not declared in this scope
 cout << ( n - x ) * x << ".0000" << endl;
                                     ^~~~