Language: C++

#include<algorithm>
#include<chrono>
#include<climits>
#include<numeric>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<random>
#include<set>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<vector>
#include<cassert>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<string>
using namespace std;
 
#define rep(i, a, b) for(auto i = (a); i < (b); i++)
#define rrep(i, a, b) for(auto i = (a); i > (b); i--)
#define all(v) (v).begin(), (v).end()
#define print(v) {for(auto x : v) cout << x << ' '; cout << endl;}
#define printn(v, n) {for(int _i = 0; _i < n; _i++) cout << *(v + _i) << ' '; cout << endl;}
 
typedef unsigned long long ull;
typedef long long ll;
 
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
 
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
 
const int MAXN = 1000 + 20;

int n, m;
double a[MAXN];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n;
    double tmp = 0;
    for(int i = 0; i < n; i++) {
    	cin >> a;
    	tmp += 1 / a;
    }
    cout << 1 / tmp << endl;

    return 0;
}











Compiler output:
a.cc: In function 'int main()':
a.cc:53:13: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'double [1020]')
   53 |         cin >> a;
      |         ~~~ ^~ ~
      |         |      |
      |         |      double [1020]
      |         std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/bits/quoted_string.h:38,
                 from /usr/include/c++/14/iomanip:50,
                 from a.cc:5:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double*'
   53 |         cin >> a;
      |                ^
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'short int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(short int)((double*)(& a))' to 'short int&'
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'short unsigned int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(short unsigned int)((double*)(& a))' to 'short unsigned int&'
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(int)((double*)(& a))' to 'int&'
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'unsigned int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(unsigned int)((double*)(& a))' to 'unsigned int&'
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'long int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(long int)((double*)(& a))' to 'long int&'
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'long unsigned int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(long unsigned int)((double*)(& a))' to 'long unsigned int&'
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'long long int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(long long int)((double*)(& a))' to 'long long int&'
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: invalid conversion from 'double*' to 'long long unsigned int' [-fpermissive]
   53 |         cin >> a;
      |                ^
      |                |
      |                double*
a.cc:53:16: error: cannot bind rvalue '(long long unsigned int)((double*)(& a))' to 'long long unsigned int&'
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:16: error: cannot bind non-const lvalue reference of type 'void*&' to an rvalue of type 'void*'
   53 |         cin >> a;
      |                ^
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:25: note:   no known conversion for argument 1 from 'double [1020]' to 'float&'
  219 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:26: note:   no known conversion for argument 1 from 'double [1020]' to 'double&'
  223 |       operator>>(double& __f)
      |                  ~~~~~~~~^~~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:31: note:   no known conversion for argument 1 from 'double [1020]' to 'long double&'
  227 |       operator>>(long double& __f)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:36: note:   no known conversion for argument 1 from 'double [1020]' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'}
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]'
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:32: note:   no known conversion for argument 1 from 'double [1020]' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char