Language: C++

#include<iostream>
#include<string>
#using namespace std;
int main()
{
string s;
cin>>s;
if(s[0]!="A"||s[2]!="C")
{
cout<<"WA"<<endl;
system("pause");
return 0;
}
for(int i=0;i<s.size();i++)
{
if(s[i]=="c")
{
a++;
}
}
if(a!=0)
{
cout<<"WA"<<endl;
system("pause");
return 0;
}
cout<<"AC"<<endl;
system("pause");
return 0;
}






Compiler output:
a.cc:3:2: error: invalid preprocessing directive #using
    3 | #using namespace std;
      |  ^~~~~
a.cc: In function 'int main()':
a.cc:6:1: error: 'string' was not declared in this scope
    6 | string s;
      | ^~~~~~
a.cc:6:1: note: suggested alternatives:
In file included from /usr/include/c++/14/iosfwd:41,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
In file included from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:7:1: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    7 | cin>>s;
      | ^~~
      | std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:7:6: error: 's' was not declared in this scope
    7 | cin>>s;
      |      ^
a.cc:10:1: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 | cout<<"WA"<<endl;
      | ^~~~
      | std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:10:13: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 | cout<<"WA"<<endl;
      |             ^~~~
      |             std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:18:1: error: 'a' was not declared in this scope
   18 | a++;
      | ^
a.cc:21:4: error: 'a' was not declared in this scope
   21 | if(a!=0)
      |    ^
a.cc:23:1: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   23 | cout<<"WA"<<endl;
      | ^~~~
      | std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:23:13: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   23 | cout<<"WA"<<endl;
      |             ^~~~
      |             std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:27:1: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   27 | cout<<"AC"<<endl;
      | ^~~~
      | std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:27:13: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   27 | cout<<"AC"<<endl;
      |             ^~~~
      |             std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~