/in/foo.c: In function 'main':
/in/foo.c:6:3: warning: statement with no effect [-Wunused-value]
  n==b*b-4*a*c;
  ~^~~~~~~~~~~
/in/foo.c:8:5: warning: value computed is not used [-Wunused-value]
   x1==(-b+sqrt(n))/(2*a);
   ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.c:9:5: warning: value computed is not used [-Wunused-value]
   x2==(-b-sqrt(n))/(2*a);
   ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.c:7:4: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  if(n>0){
    ^
/in/foo.c:11:2: warning: 'x2' is used uninitialized in this function [-Wuninitialized]
  printf("%.2f,%.2f",x1,x2);
  ^~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.c:11:2: warning: 'x1' is used uninitialized in this function [-Wuninitialized]