/in/foo.c: In function 'main':
/in/foo.c:8:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%d",&x);
  ^~~~~
/in/foo.c:8:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:8:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:9:6: warning: variable 'x1' set but not used [-Wunused-but-set-variable]
  int x1;
      ^~
/in/foo.c: In function 'Output':
/in/foo.c:45:3: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   printf("%d",a[i]);
   ^~~~~~
/in/foo.c:45:3: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:45:3: note: include '<stdio.h>' or provide a declaration of 'printf'