/in/foo.c: In function 'main':
/in/foo.c:28:39: error: 'n' undeclared (first use in this function)
   printf("%.2f+%.2fi\n%.2f-%.2fi\n",p,n,p,n);
                                       ^
/in/foo.c:28:39: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:6:33: warning: variable 'm' set but not used [-Wunused-but-set-variable]
     double a,b,c,x1,x2,disc,q,p,m;
                                 ^