decoder.cpp: In function 'int decode(int, int, int)':
decoder.cpp:7:9: error: request for member 'back' in 'h', which is of non-class type 'int'
7 | a+=(h.back()-'0')*ceil(pow(10,i));
| ^~~~
decoder.cpp:8:5: error: request for member 'pop_back' in 'h', which is of non-class type 'int'
8 | h.pop_back();
| ^~~~~~~~
decoder.cpp:10:14: error: no matching function for call to 'stoi(int&)'
10 | int b=stoi(h);
| ^
In file included from /usr/include/c++/10/string:55,
from /usr/include/c++/10/bits/locale_classes.h:40,
from /usr/include/c++/10/bits/ios_base.h:41,
from /usr/include/c++/10/ios:42,
from /usr/include/c++/10/istream:38,
from /usr/include/c++/10/sstream:38,
from /usr/include/c++/10/complex:45,
from /usr/include/c++/10/ccomplex:39,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
from decoder.cpp:1:
/usr/include/c++/10/bits/basic_string.h:6546:3: note: candidate: 'int std::__cxx11::stoi(const string&, std::size_t*, int)'
6546 | stoi(const string& __str, size_t* __idx = 0, int __base = 10)
| ^~~~
/usr/include/c++/10/bits/basic_string.h:6546:22: note: no known conversion for argument 1 from 'int' to 'const string&' {aka 'const std::__cxx11::basic_string<char>&'}
6546 | stoi(const string& __str, size_t* __idx = 0, int __base = 10)
| ~~~~~~~~~~~~~~^~~~~
/usr/include/c++/10/bits/basic_string.h:6677:3: note: candidate: 'int std::__cxx11::stoi(const wstring&, std::size_t*, int)'
6677 | stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
| ^~~~
/usr/include/c++/10/bits/basic_string.h:6677:23: note: no known conversion for argument 1 from 'int' to 'const wstring&' {aka 'const std::__cxx11::basic_string<wchar_t>&'}
6677 | stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
| ~~~~~~~~~~~~~~~^~~~~