Language: C++

#include<iostream>
#include<vector>
 
int main()
{
    int w,n;
 
    char c;
 
  cin >> w >> n;
 
 vector<int> a(n);
 
    vector<int> b(n);
 
    vector<int> x(w);
 
    for(int i=0;i<n;++i)
    {
        std::cin >> a[i] >> c >> b[i];
    }
 
    for(int i=0;i<w;++i)
    {
        x[i]=i+1;
    }
 
    for(int i=0;i<n;++i)
    {
        int temp = x[a[i]-1];
 
        x[a[i]-1]=x[b[i]-1];
 
        x[b[i]-1]=temp;
    }
 
    for(int i=0;i<w;++i)
    {
      cout << x[i] << endl;
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   10 |   cin >> w >> n;
      |   ^~~
      |   std::cin
In file included from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:12:2: error: 'vector' was not declared in this scope
   12 |  vector<int> a(n);
      |  ^~~~~~
a.cc:12:2: note: suggested alternatives:
In file included from /usr/include/c++/14/vector:66,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_vector.h:428:11: note:   'std::vector'
  428 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
/usr/include/c++/14/vector:93:13: note:   'std::pmr::vector'
   93 |       using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>;
      |             ^~~~~~
a.cc:12:9: error: expected primary-expression before 'int'
   12 |  vector<int> a(n);
      |         ^~~
a.cc:14:12: error: expected primary-expression before 'int'
   14 |     vector<int> b(n);
      |            ^~~
a.cc:16:12: error: expected primary-expression before 'int'
   16 |     vector<int> x(w);
      |            ^~~
a.cc:20:21: error: 'a' was not declared in this scope
   20 |         std::cin >> a[i] >> c >> b[i];
      |                     ^
a.cc:20:34: error: 'b' was not declared in this scope
   20 |         std::cin >> a[i] >> c >> b[i];
      |                                  ^
a.cc:25:9: error: 'x' was not declared in this scope
   25 |         x[i]=i+1;
      |         ^
a.cc:30:20: error: 'x' was not declared in this scope
   30 |         int temp = x[a[i]-1];
      |                    ^
a.cc:30:22: error: 'a' was not declared in this scope
   30 |         int temp = x[a[i]-1];
      |                      ^
a.cc:32:21: error: 'b' was not declared in this scope
   32 |         x[a[i]-1]=x[b[i]-1];
      |                     ^
a.cc:39:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   39 |       cout << x[i] << 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:39:15: error: 'x' was not declared in this scope
   39 |       cout << x[i] << endl;
      |               ^
a.cc:39:23: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   39 |       cout << x[i] << endl;
      |                       ^~~~
      |                       std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~