/in/foo.c: In function 'main':
/in/foo.c:17:16: error: 'n' undeclared (first use in this function)
   17 |         int a1[n], a2[n];
      |                ^
/in/foo.c:17:16: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:28:9: error: 'cout' undeclared (first use in this function)
   28 |         cout<<"%d ", a1[i]<<endl;
      |         ^~~~
/in/foo.c:28:29: error: 'endl' undeclared (first use in this function)
   28 |         cout<<"%d ", a1[i]<<endl;
      |                             ^~~~
/in/foo.c:28:20: warning: left-hand operand of comma expression has no effect [-Wunused-value]
   28 |         cout<<"%d ", a1[i]<<endl;
      |                    ^
/in/foo.c:31:29: error: 'xn2' undeclared (first use in this function); did you mean 'xn1'?
   31 |         for (int i = 0; i < xn2; i++) {
      |                             ^~~
      |                             xn1
/in/foo.c:32:20: warning: left-hand operand of comma expression has no effect [-Wunused-value]
   32 |         cout<<"%d ", a1[i]<<endl;
      |                    ^
/in/foo.c:17:20: warning: unused variable 'a2' [-Wunused-variable]
   17 |         int a1[n], a2[n];
      |                    ^~
/in/foo.c:17:13: warning: unused variable 'a1' [-Wunused-variable]
   17 |         int a1[n], a2[n];
      |             ^~