Language: C++

#include<stdio.h>
#include<string>
#include<iostream>
using namespace std;

std::string substrBack(std::string str, size_t pos, size_t len) {
	const size_t strLen = str.length();

	return str.substr(strLen - pos, len);
}


int main(void) {
	int n, k, i,len;
	int flag = 1;
	cin >> n;
	string s[110][15];
	string x, y;
	for (i = 0; i < n; i++) {
		cin >> s[i];
	}
	for (i = 0; i < n-1; i++) {
	  len = strlen(s[i+1]);
	  x = substrBack(s[i], 1, 1);
	  y = substrBack(s[i + 1], len, 1);
	  if (x == y) {
		  printf("No\n");
		  flag = 0;
		  break;
	  }


	}
	if (flag = 1) {
		for (i = 0; i < n; i++) {
			for (k = 0; k < n; k++) {
				if (s[i] == s[k]) {
					printf("No\n");
					flag = 0;
					goto end;
				}
			}
		}
		printf("Yes\n");
	}

	end:
	

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:20:21: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'std::string [15]' {aka 'std::__cxx11::basic_string<char> [15]'})
   20 |                 cin >> s[i];
      |                 ~~~ ^~ ~~~~
      |                 |         |
      |                 |         std::string [15] {aka std::__cxx11::basic_string<char> [15]}
      |                 std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/iostream:42,
                 from a.cc:3:
/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:20:27: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'std::string*' {aka 'std::__cxx11::basic_string<char>*'}
   20 |                 cin >> s[i];
      |                        ~~~^
/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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'short int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(short int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'short unsigned int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(short unsigned int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'unsigned int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(unsigned int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(long int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long unsigned int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(long unsigned int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long long int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(long long int)((std::string*)(& s[i]))' 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:20:27: error: invalid conversion from 'std::string*' {aka 'std::__cxx11::basic_string<char>*'} to 'long long unsigned int' [-fpermissive]
   20 |                 cin >> s[i];
      |                        ~~~^
      |                           |
      |                           std::string* {aka std::__cxx11::basic_string<char>*}
a.cc:20:27: error: cannot bind rvalue '(long long unsigned int)((std::string*)(& s[i]))' 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:20:27: error: cannot bind non-const lvalue reference of type 'void*&' to an rvalue of type 'void*'
   20 |                 cin >> s[i];
      |                        ~~~^
/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::string [15]' {aka 'std::__cxx11::basic_string<char> [15]'} 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::string [15]' {aka 'std::__cxx11::basic_string<char> [15]'} 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::string [15]' {aka 'std::__cxx11::basic_string<char> [15]'} to 'long double&'
  227 |