/in/foo.c: In function 'main':
/in/foo.c:13:6: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   sum=sum+x;
   ~~~^~~~~~
/in/foo.c: In function 'Fib':
/in/foo.c:23:15: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int a=1, b=1,c;
               ^