C++ 我在重载操作符时遇到了一个问题&燃气轮机&燃气轮机&引用；我不知道'；我不知道发生了什么事
我读过其他针对类似问题的回复，但没有任何效果。这些回答建议包括C++ 我在重载操作符时遇到了一个问题&燃气轮机&燃气轮机&引用；我不知道'；我不知道发生了什么事,c++,operator-overloading,C++,Operator Overloading,我读过其他针对类似问题的回复，但没有任何效果。这些回答建议包括#包括，但这不起作用。此外，我还尝试在User类中创建重载friend函数，但没有成功 这是用户类： 类用户 { 布尔状态； std:：string first_name； std:：字符串last_name； 公众： 静态int用户计数； 用户（） { 状态=0； first_name=“first”； last_name=“last”； 用户计数++； } 用户（std:：string new_first，std:：string
#包括，但这不起作用。此外，我还尝试在User
类中创建重载friend
函数，但没有成功
这是用户
类：
类用户
{
布尔状态；
std:：string first_name；
std:：字符串last_name；
公众：
静态int用户计数；
用户（）
{
状态=0；
first_name=“first”；
last_name=“last”；
用户计数++；
}
用户（std:：string new_first，std:：string new_last，bool new_status）
{
first\u name=新的\u first；
last\u name=新的\u last；
状态=新状态；
用户计数++；
}
//一些能手和二传手。。。
~User（）
{
用户计数--；
}
friend std:：ostream&operator（std:：istream&，User&）；
};
是的，我在类外初始化了user\u count
这些是重载：
std:：ostream&operator user.last_name>>user.status；
返回输入；
}
这是main（）
函数：
intmain（）
{
User（）；
std:：cin>>用户；
std:：cout'（操作数类型为'std:：istream'{aka'std:：basic_istream'}和'User（'））
75 |标准：：cin>>用户；
| ~~~~~~~~ ^~ ~~~~
| | |
||用户（）
|std:：istream{aka std:：basic_istream}
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:120:7：注：候选者：'std:：basic\u isttream:：'u\u isttream类型&std:：basic\u isttream:：operator>>（std:：basic\u isttream:：'u isttream类型&（*）（std:：basic\u isttream:：：'u\u isttream类型&）[带CharT；\u Traits=std:：CharT\u Traits=std:：char Traits；std:：basic\u isttream:：'
120 |运算符>>（uu istream_type&（*uu pf）（uu istream_type&））
| ^~~~~~~~
/usr/include/c++/9/istream:120:7:注意：参数1的转换格式不正确：
main.cpp:75:17:错误：从“User（*）到“std:：basic_istream:：__istream_type&（*）（std:：basic_istream:：_istream_type&）的转换无效。{aka'std:：basic_istream&（*）（std:：basic_istream&'）}[-fpermissive]
75 |标准：：cin>>用户；
| ^~~~
| |
|用户（*）（）
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:124:7：注：候选者：'std：：基本istream:：'基本istream类型&std：：基本istream：：运算符>>（std：：基本istream:：'基本ios类型&（*）（std：：基本ios类型：：'基本ios类型&）[带字符；'字符特征=std：：字符特征；std：：基本istream
124 |运算符>>（uuiOS_U类型和（*uuU pf）（uiOS_U类型和））
| ^~~~~~~~
/usr/include/c++/9/istream:124:7:注意：参数1的转换格式不正确：
main.cpp:75:17:错误：从“User（*）到“std:：basic_-ios-type&（*）（std:：basic_-ios-type:：_-ios-type&）的转换无效，{aka'std:：basic_-ios&（*）（std:：basic_-ios&'）}[-fppermission]
75 |标准：：cin>>用户；
| ^~~~
| |
|用户（*）（）
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:131:7：注：候选者：'std:：basic\u istream:：'uu istream\u type&std:：basic\u istream:：operator>>（std:：ios\u base&（*）（std:：ios\u base&）[带CharT=char；\u Traits=std:：char\u traitributes；std:：basic\u istream:：：：'uu istream\u type=std:：basic\u istream:'
131 |运营商>>（ios|U基地和（*|U pf）（ios|U基地和）
| ^~~~~~~~
/usr/include/c++/9/istream:131:7:注意：参数1的转换格式不正确：
main.cpp:75:17:错误：从“用户（*）（）到“std:：ios_base&（*）（std:：ios_base&））的转换无效[-fppermissive]
75 |标准：：cin>>用户；
| ^~~~
| |
|用户（*）（）
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:168:7：注：候选者：'std:：basic\u istream:：'uuuuuuiStream\u type&std:：basic\u istream:：operator>>（bool&）[with CharT=char；Traits=std:：char\u Traits；std:：basic\u istream:：：'uuuuuuuuiStream\u type=std:：basic\u istream]'
168 |运算符>>（布尔和| n）
| ^~~~~~~~
/usr/include/c++/9/istream:168:7:注意：参数1的转换格式不正确：
main.cpp:75:17:错误：无法将类型为“bool&”的非常量左值引用绑定到类型为“bool”的右值
75 |标准：：cin>>用户；
| ^~~~
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:172:7：注：候选者：“std:：basic\u istream&std:：basic\u istream:：operator>>（短int&）[带_CharT=char；_Traits=std:：char\u Traits]”
172 |运算符>>（短和| n）；
| ^~~~~~~~
/usr/include/c++/9/istream:172:7:注意：参数1的转换格式不正确：
main.cpp:75:17:错误：从“User（*）（）到“short int”[-fppermissive]的转换无效
75 |标准：：cin>>用户；
| ^~~~
| |
|用户（*）（）
main.cpp:75:17:错误：无法将右值“（短int）用户”绑定到“短int&”
在/usr/include/c++/9/iostream:40中包含的文件中，
来自main.cpp:1：
/usr/include/c++/9/istream:175:7：注：候选者：'std:：basic\u isttream:：'u\u isttream\u type&std:：basic\u isttream:：operator>>（短无符号int&）[带字符；\u Traits=std:：char\u Traits；std:：basic\u isttream:：\u isttream\u type=std:：basic\u
main.cpp: In function ‘int main()’:
main.cpp:75:14: error: no match for ‘operator>>’ (operand types are ‘std::istream’ {aka ‘std::basic_istream<char>’} and ‘User(’)
75 | std::cin >> user;
| ~~~~~~~~ ^~ ~~~~
| | |
| | User()
| std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:120:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__istream_type& (*)(std::basic_istream<_CharT, _Traits>::__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
120 | operator>>(__istream_type& (*__pf)(__istream_type&))
| ^~~~~~~~
/usr/include/c++/9/istream:120:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)’ {aka ‘std::basic_istream<char>& (*)(std::basic_istream<char>&)’} [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:124:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__ios_type& (*)(std::basic_istream<_CharT, _Traits>::__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>; std::basic_istream<_CharT, _Traits>::__ios_type = std::basic_ios<char>]’ <near match>
124 | operator>>(__ios_type& (*__pf)(__ios_type&))
| ^~~~~~~~
/usr/include/c++/9/istream:124:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)’ {aka ‘std::basic_ios<char>& (*)(std::basic_ios<char>&)’} [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:131:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
131 | operator>>(ios_base& (*__pf)(ios_base&))
| ^~~~~~~~
/usr/include/c++/9/istream:131:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘std::ios_base& (*)(std::ios_base&)’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:168:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
168 | operator>>(bool& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:168:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: cannot bind non-const lvalue reference of type ‘bool&’ to an rvalue of type ‘bool’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:172:7: 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>
172 | operator>>(short& __n);
| ^~~~~~~~
/usr/include/c++/9/istream:172:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘short int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(short int)user’ to ‘short int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:175:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
175 | operator>>(unsigned short& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:175:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘short unsigned int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(short unsigned int)user’ to ‘short unsigned int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:179:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]’ <near match>
179 | operator>>(int& __n);
| ^~~~~~~~
/usr/include/c++/9/istream:179:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(int)user’ to ‘int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:182:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
182 | operator>>(unsigned int& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:182:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘unsigned int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(unsigned int)user’ to ‘unsigned int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:186:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
186 | operator>>(long& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:186:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘long int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(long int)user’ to ‘long int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:190:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
190 | operator>>(unsigned long& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:190:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘long unsigned int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(long unsigned int)user’ to ‘long unsigned int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:195:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
195 | operator>>(long long& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:195:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘long long int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(long long int)user’ to ‘long long int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:199:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
199 | operator>>(unsigned long long& __n)
| ^~~~~~~~
/usr/include/c++/9/istream:199:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘long long unsigned int’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(long long unsigned int)user’ to ‘long long unsigned int&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:235:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’ <near match>
235 | operator>>(void*& __p)
| ^~~~~~~~
/usr/include/c++/9/istream:235:7: note: conversion of argument 1 would be ill-formed:
main.cpp:75:17: error: invalid conversion from ‘User (*)()’ to ‘void*’ [-fpermissive]
75 | std::cin >> user;
| ^~~~
| |
| User (*)()
main.cpp:75:17: error: cannot bind rvalue ‘(void*)user’ to ‘void*&’
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:214:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’
214 | operator>>(float& __f)
| ^~~~~~~~
/usr/include/c++/9/istream:214:25: note: no known conversion for argument 1 from ‘User()’ to ‘float&’
214 | operator>>(float& __f)
| ~~~~~~~^~~
/usr/include/c++/9/istream:218:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’
218 | operator>>(double& __f)
| ^~~~~~~~
/usr/include/c++/9/istream:218:26: note: no known conversion for argument 1 from ‘User()’ to ‘double&’
218 | operator>>(double& __f)
| ~~~~~~~~^~~
/usr/include/c++/9/istream:222:7: 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>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]’
222 | operator>>(long double& __f)
| ^~~~~~~~
/usr/include/c++/9/istream:222:31: note: no known conversion for argument 1 from ‘User()’ to ‘long double&’
222 | operator>>(long double& __f)
| ~~~~~~~~~~~~~^~~
/usr/include/c++/9/istream:259:7: note: candidate: ‘std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__streambuf_type*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]’
259 | operator>>(__streambuf_type* __sb);
| ^~~~~~~~
/usr/include/c++/9/istream:259:36: note: no known conversion for argument 1 from ‘User()’ to ‘std::basic_istream<char>::__streambuf_type*’ {aka ‘std::basic_streambuf<char>*’}
259 | operator>>(__streambuf_type* __sb);
| ~~~~~~~~~~~~~~~~~~^~~~
main.cpp:65:15: note: candidate: ‘std::istream& operator>>(std::istream&, User&)’
65 | std::istream& operator >>(std::istream& input, User& user)
| ^~~~~~~~
main.cpp:65:54: note: no known conversion for argument 2 from ‘User()’ to ‘User&’
65 | std::istream& operator >>(std::istream& input, User& user)
| ~~~~~~^~~~
In file included from /usr/include/c++/9/string:56,
from /usr/include/c++/9/bits/locale_classes.h:40,
from /usr/include/c++/9/bits/ios_base.h:41,
from /usr/include/c++/9/ios:42,
from /usr/include/c++/9/ostream:38,
from /usr/include/c++/9/iostream:39,
from main.cpp:1:
/usr/include/c++/9/bits/basic_string.tcc:1466:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)’
1466 | operator>>(basic_istream<_CharT, _Traits>& __in,
| ^~~~~~~~
/usr/include/c++/9/bits/basic_string.tcc:1466:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: mismatched types ‘std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘User()’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/istream:991,
from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/bits/istream.tcc:931:5: note: candidate: ‘template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT&)’
931 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
| ^~~~~~~~
/usr/include/c++/9/bits/istream.tcc:931:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: deduced conflicting types for parameter ‘_CharT’ (‘char’ and ‘User()’)
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:756:5: note: candidate: ‘template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char&)’
756 | operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
| ^~~~~~~~
/usr/include/c++/9/istream:756:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: cannot convert ‘user’ (type ‘User()’) to type ‘unsigned char&’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:761:5: note: candidate: ‘template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char&)’
761 | operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
| ^~~~~~~~
/usr/include/c++/9/istream:761:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: cannot convert ‘user’ (type ‘User()’) to type ‘signed char&’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/istream:991,
from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/bits/istream.tcc:963:5: note: candidate: ‘template<class _CharT2, class _Traits2> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT2*)’
963 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
| ^~~~~~~~
/usr/include/c++/9/bits/istream.tcc:963:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: deduced conflicting types for parameter ‘_CharT2’ (‘char’ and ‘User()’)
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:803:5: note: candidate: ‘template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char*)’
803 | operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
| ^~~~~~~~
/usr/include/c++/9/istream:803:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: cannot convert ‘user’ (type ‘User()’) to type ‘unsigned char*’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:808:5: note: candidate: ‘template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char*)’
808 | operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
| ^~~~~~~~
/usr/include/c++/9/istream:808:5: note: template argument deduction/substitution failed:
main.cpp:75:17: note: cannot convert ‘user’ (type ‘User()’) to type ‘signed char*’
75 | std::cin >> user;
| ^~~~
In file included from /usr/include/c++/9/iostream:40,
from main.cpp:1:
/usr/include/c++/9/istream:980:5: note: candidate: ‘template<class _Istream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable<typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type, _Tp&&, void> >::value, typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type>::type std::operator>>(_Istream&&, _Tp&&)’
980 | operator>>(_Istream&& __is, _Tp&& __x)
| ^~~~~~~~
/usr/include/c++/9/istream:980:5: note: template argument deduction/substitution failed:
/usr/include/c++/9/istream: In substitution of ‘template<class _Istream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable<typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type, _Tp&&, void> >::value, typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type>::type std::operator>>(_Istream&&, _Tp&&) [with _Istream = std::basic_istream<char>&; _Tp = User (&)()]’:
main.cpp:75:17: required from here
/usr/include/c++/9/istream:980:5: error: no type named ‘type’ in ‘struct std::enable_if<false, std::basic_istream<char>&>’