Language: C++

#include<iostream>
int main() {
	typedef unsigned short int mew;
	mew mountain[10];
	for (int i = 0; i < 10; i++) {
		cin >> mountain[i];
	}

	mew taller[3];
	mew a, b, c;

	a = mountain[0];
	b = mountain[1];
	c = mountain[2];

	for (int y = 3; y <= 9; y++) {
		if (a<=b){
			if (a<=c){
				if (a < mountain[y]) {
				???a = mountain[y];}
			}
			else{
				if (c < mountain[y]) {
					c = mountain[y];}
			}
		}
		else if (b<=c)
		{
			if (b < mountain[y]) {
				b = mountain[y];}
		}
	}

	//biggest->taller[0],bigger->taller[1],taller[2]
	{
		if (a >= b&&a >= c)
		{
			taller[0] = a;
			if (b >= c)
			{
				taller[1] = b;
				taller[2] = c;
			}
			else {
				taller[1] = c;
				taller[2] = b;
			}
		}
		if (b >= a&&b >= c)
		{
			taller[0] = b;
			if (a >= c)
			{
				taller[1] = a;
				taller[2] = c;
			}
			else {
				taller[1] = c;
				taller[2] = a;
			}
		}
		if (c >= b&&c >= a)
		{
			taller[0] = c;
			if (b >= a)
			{
				taller[1] = b;
				taller[2] = a;
			}
			else {
				taller[1] = a;
				taller[2] = b;
			}
		}
	} 

	cout << taller[0] << endl;
	cout << taller[1] << endl;
	cout << taller[2] << endl;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:17: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |                 cin >> mountain[i];
      |                 ^~~
      |                 std::cin
In file included from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:20:33: error: expected primary-expression before '?' token
   20 |                                 ???a = mountain[y];}
      |                                 ^
a.cc:20:34: error: expected primary-expression before '?' token
   20 |                                 ???a = mountain[y];}
      |                                  ^
a.cc:20:35: error: expected primary-expression before '?' token
   20 |                                 ???a = mountain[y];}
      |                                   ^
a.cc:20:51: error: expected ':' before ';' token
   20 |                                 ???a = mountain[y];}
      |                                                   ^
      |                                                   :
a.cc:20:51: error: expected primary-expression before ';' token
a.cc:20:51: error: expected ':' before ';' token
   20 |                                 ???a = mountain[y];}
      |                                                   ^
      |                                                   :
a.cc:20:51: error: expected primary-expression before ';' token
a.cc:20:51: error: expected ':' before ';' token
   20 |                                 ???a = mountain[y];}
      |                                                   ^
      |                                                   :
a.cc:20:51: error: expected primary-expression before ';' token
a.cc:77:9: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   77 |         cout << taller[0] << endl;
      |         ^~~~
      |         std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:77:30: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   77 |         cout << taller[0] << endl;
      |                              ^~~~
      |                              std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~