Main.cc: In function ‘int main()’: Main.cc:6:5: error: no match for ‘operator>>’ (operand types are ‘std::istream {aka std::basic_istream}’ and ‘int [100]’) cin>>a; ~~~^~~ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(bool& __n) ^~~~~~~~ /usr/include/c++/7/istream:168:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: cannot bind non-const lvalue reference of type ‘bool&’ to an rvalue of type ‘bool’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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] operator>>(short& __n); ^~~~~~~~ /usr/include/c++/7/istream:172:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘short int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(short int)((int*)(& a))’ to ‘short int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(unsigned short& __n) ^~~~~~~~ /usr/include/c++/7/istream:175:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘short unsigned int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(short unsigned int)((int*)(& a))’ to ‘short unsigned int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:179:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits] operator>>(int& __n); ^~~~~~~~ /usr/include/c++/7/istream:179:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(int)((int*)(& a))’ to ‘int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(unsigned int& __n) ^~~~~~~~ /usr/include/c++/7/istream:182:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘unsigned int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(unsigned int)((int*)(& a))’ to ‘unsigned int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(long& __n) ^~~~~~~~ /usr/include/c++/7/istream:186:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘long int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(long int)((int*)(& a))’ to ‘long int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(unsigned long& __n) ^~~~~~~~ /usr/include/c++/7/istream:190:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘long unsigned int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(long unsigned int)((int*)(& a))’ to ‘long unsigned int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(long long& __n) ^~~~~~~~ /usr/include/c++/7/istream:195:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘long long int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(long long int)((int*)(& a))’ to ‘long long int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(unsigned long long& __n) ^~~~~~~~ /usr/include/c++/7/istream:199:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: invalid conversion from ‘int*’ to ‘long long unsigned int’ [-fpermissive] cin>>a; ^ Main.cc:6:7: error: cannot bind rvalue ‘(long long unsigned int)((int*)(& a))’ to ‘long long unsigned int&’ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(void*& __p) ^~~~~~~~ /usr/include/c++/7/istream:235:7: note: conversion of argument 1 would be ill-formed: Main.cc:6:7: error: cannot bind non-const lvalue reference of type ‘void*&’ to an rvalue of type ‘void*’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(__istream_type& (*__pf)(__istream_type&)) ^~~~~~~~ /usr/include/c++/7/istream:120:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘std::basic_istream::__istream_type& (*)(std::basic_istream::__istream_type&) {aka std::basic_istream& (*)(std::basic_istream&)}’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream; std::basic_istream<_CharT, _Traits>::__ios_type = std::basic_ios] operator>>(__ios_type& (*__pf)(__ios_type&)) ^~~~~~~~ /usr/include/c++/7/istream:124:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘std::basic_istream::__ios_type& (*)(std::basic_istream::__ios_type&) {aka std::basic_ios& (*)(std::basic_ios&)}’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(ios_base& (*__pf)(ios_base&)) ^~~~~~~~ /usr/include/c++/7/istream:131:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘std::ios_base& (*)(std::ios_base&)’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(float& __f) ^~~~~~~~ /usr/include/c++/7/istream:214:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘float&’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(double& __f) ^~~~~~~~ /usr/include/c++/7/istream:218:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘double&’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream] operator>>(long double& __f) ^~~~~~~~ /usr/include/c++/7/istream:222:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘long double&’ /usr/include/c++/7/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; std::basic_istream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf] operator>>(__streambuf_type* __sb); ^~~~~~~~ /usr/include/c++/7/istream:259:7: note: no known conversion for argument 1 from ‘int [100]’ to ‘std::basic_istream::__streambuf_type* {aka std::basic_streambuf*}’ In file included from /usr/include/c++/7/string:53:0, from /usr/include/c++/7/bits/locale_classes.h:40, from /usr/include/c++/7/bits/ios_base.h:41, from /usr/include/c++/7/ios:42, from /usr/include/c++/7/ostream:38, from /usr/include/c++/7/iostream:39, from Main.cc:1: /usr/include/c++/7/bits/basic_string.tcc:1465:5: note: candidate: template std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) operator>>(basic_istream<_CharT, _Traits>& __in, ^~~~~~~~ /usr/include/c++/7/bits/basic_string.tcc:1465:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: mismatched types ‘std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘int [100]’ cin>>a; ^ In file included from /usr/include/c++/7/istream:991:0, from /usr/include/c++/7/iostream:40, from Main.cc:1: /usr/include/c++/7/bits/istream.tcc:963:5: note: candidate: template std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT2*) operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s) ^~~~~~~~ /usr/include/c++/7/bits/istream.tcc:963:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: deduced conflicting types for parameter ‘_CharT2’ (‘char’ and ‘int’) cin>>a; ^ In file included from /usr/include/c++/7/istream:991:0, from /usr/include/c++/7/iostream:40, from Main.cc:1: /usr/include/c++/7/bits/istream.tcc:931:5: note: candidate: template std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT&) operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c) ^~~~~~~~ /usr/include/c++/7/bits/istream.tcc:931:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: deduced conflicting types for parameter ‘_CharT’ (‘char’ and ‘int [100]’) cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:756:5: note: candidate: template std::basic_istream& std::operator>>(std::basic_istream&, unsigned char&) operator>>(basic_istream& __in, unsigned char& __c) ^~~~~~~~ /usr/include/c++/7/istream:756:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: cannot convert ‘a’ (type ‘int [100]’) to type ‘unsigned char&’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:761:5: note: candidate: template std::basic_istream& std::operator>>(std::basic_istream&, signed char&) operator>>(basic_istream& __in, signed char& __c) ^~~~~~~~ /usr/include/c++/7/istream:761:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: cannot convert ‘a’ (type ‘int [100]’) to type ‘signed char&’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:803:5: note: candidate: template std::basic_istream& std::operator>>(std::basic_istream&, unsigned char*) operator>>(basic_istream& __in, unsigned char* __s) ^~~~~~~~ /usr/include/c++/7/istream:803:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: cannot convert ‘a’ (type ‘int [100]’) to type ‘unsigned char*’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:808:5: note: candidate: template std::basic_istream& std::operator>>(std::basic_istream&, signed char*) operator>>(basic_istream& __in, signed char* __s) ^~~~~~~~ /usr/include/c++/7/istream:808:5: note: template argument deduction/substitution failed: Main.cc:6:7: note: cannot convert ‘a’ (type ‘int [100]’) to type ‘signed char*’ cin>>a; ^ In file included from /usr/include/c++/7/iostream:40:0, from Main.cc:1: /usr/include/c++/7/istream:980:5: note: candidate: template typename std::enable_if >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable::__istream_type, _Tp&&, void> >::value, typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type>::type std::operator>>(_Istream&&, _Tp&&) operator>>(_Istream&& __is, _Tp&& __x) ^~~~~~~~ /usr/include/c++/7/istream:980:5: note: template argument deduction/substitution failed: /usr/include/c++/7/istream: In substitution of ‘template typename std::enable_if >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable::__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&; _Tp = int (&)[100]]’: Main.cc:6:7: required from here /usr/include/c++/7/istream:980:5: error: no type named ‘type’ in ‘struct std::enable_if&>’