Language: C++

#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)n;i++)
int main(){
    int n,m;
    cin>>n>>m;
    vector<int> a(m);
    vector<int> b(m);
    vector<int> c(n,0);
    rep(i,m){
        cin>>a.at(i)>>cin>>b.at(i);
        cout<<endl;
    }
    rep(i,n){
        c.at(a.at(i)-1)++;
        c.at(b.at(i)-1)++;
    }
    rep(i,n){
        cout>>c.at(i);
    }

    cout<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:21: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'std::istream' {aka 'std::basic_istream<char>'})
   11 |         cin>>a.at(i)>>cin>>b.at(i);
      |         ~~~~~~~~~~~~^~~~~
      |            |          |
      |            |          basic_istream<[...]>
      |            basic_istream<[...]>
a.cc:11:21: note: candidate: 'operator>>(int, int)' (built-in)
   11 |         cin>>a.at(i)>>cin>>b.at(i);
      |         ~~~~~~~~~~~~^~~~~
a.cc:11:21: note:   no known conversion for argument 2 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int'
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/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>]'
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:24: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'bool&'
  170 |       operator>>(bool& __n)
      |                  ~~~~~~^~~
/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>]'
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:25: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'short int&'
  174 |       operator>>(short& __n);
      |                  ~~~~~~~^~~
/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>]'
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:34: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'short unsigned int&'
  177 |       operator>>(unsigned short& __n)
      |                  ~~~~~~~~~~~~~~~~^~~
/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>]'
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:23: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int&'
  181 |       operator>>(int& __n);
      |                  ~~~~~^~~
/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>]'
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:32: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'unsigned int&'
  184 |       operator>>(unsigned int& __n)
      |                  ~~~~~~~~~~~~~~^~~
/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>]'
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:24: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'long int&'
  188 |       operator>>(long& __n)
      |                  ~~~~~~^~~
/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>]'
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:33: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'long unsigned int&'
  192 |       operator>>(unsigned long& __n)
      |                  ~~~~~~~~~~~~~~~^~~
/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>]'
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:29: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'long long int&'
  199 |       operator>>(long long& __n)
      |                  ~~~~~~~~~~~^~~
/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>]'
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:38: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'long long unsigned int&'
  203 |       operator>>(unsigned long long& __n)
      |                  ~~~~~~~~~~~~~~~~~~~~^~~
/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 'std::istream' {aka 'std::basic_istream<char>'} 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 'std::istream' {aka 'std::basic_istream<char>'} 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 'std::istream' {aka 'std::basic_istream<char>'} to 'long double&'
  227 |       operator>>(long double& __f)
      |                  ~~~~~~~~~~~~~^~~
/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>]'
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:25: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'void*&'
  328 |       operator>>(void*& __p)
      |                  ~~~~~~~^~~
/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 'std::istream' {aka 'std::basic_istream<char>'} 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 'std::istream' {aka 'std::basic_istream<char>'} to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:133:7: 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>; __istream_type = std::basic_istream<char>]'
  133 |       operator>>(ios_base& (*__pf)(ios_base&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:133:30: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'std::ios_base& (*)(std::ios_base&)'