/in/foo.c: In function 'main':
/in/foo.c:8:11: warning: format '%lf' expects argument of type 'double *', but argument 2 has type 'float *' [-Wformat=]
  scanf("%lf %lf",&ax,&ay);
           ^
/in/foo.c:8:15: warning: format '%lf' expects argument of type 'double *', but argument 3 has type 'float *' [-Wformat=]
  scanf("%lf %lf",&ax,&ay);
               ^
/in/foo.c:13:11: warning: format '%lf' expects argument of type 'double *', but argument 2 has type 'float *' [-Wformat=]
  scanf("%lf %lf",&bx,&by);
           ^
/in/foo.c:13:15: warning: format '%lf' expects argument of type 'double *', but argument 3 has type 'float *' [-Wformat=]
  scanf("%lf %lf",&bx,&by);
               ^
/in/foo.c:15:12: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
  float dis=sqrt((ax-bx)*(ax-bx)+(ay-by)*(ay-by));
            ^~~~
/in/foo.c:15:12: warning: incompatible implicit declaration of built-in function 'sqrt'
/in/foo.c:15:12: note: include '<math.h>' or provide a declaration of 'sqrt'
/in/foo.c:23:8: warning: unused variable 'add' [-Wunused-variable]
  float add=(vector_mul+ax*bx+ay*by-ax*ax-ay*ay)/(bx-ay);
        ^~~
/in/foo.c:17:11: warning: unused variable 'cy' [-Wunused-variable]
  float cx,cy;
           ^~
/in/foo.c:17:8: warning: unused variable 'cx' [-Wunused-variable]
  float cx,cy;
        ^~