/in/foo.c: In function 'main':
/in/foo.c:15:3: warning: implicit declaration of function 'MoveLeft' [-Wimplicit-function-declaration]
   MoveLeft(a,n);
   ^~~~~~~~
/in/foo.c: At top level:
/in/foo.c:23:6: warning: conflicting types for 'MoveLeft'
 void MoveLeft(int a[],int n)
      ^~~~~~~~
/in/foo.c:15:3: note: previous implicit declaration of 'MoveLeft' was here
   MoveLeft(a,n);
   ^~~~~~~~