/in/foo.c: In function 'main':
/in/foo.c:7:2: error: expected ';' before 'while'
  while(n>=2)
  ^~~~~
/in/foo.c:5:19: warning: unused variable 'k' [-Wunused-variable]
     int n,a=1,i=1,k=0;
                   ^
/in/foo.c:5:15: warning: unused variable 'i' [-Wunused-variable]
     int n,a=1,i=1,k=0;
               ^
/in/foo.c:5:11: warning: unused variable 'a' [-Wunused-variable]
     int n,a=1,i=1,k=0;
           ^