/in/foo.c: In function 'main':
/in/foo.c:6:6: error: called object is not a function or function pointer
 s=a1*10(3-1)+a2*(3-2)+a3*10(3-3);
      ^~
/in/foo.c:6:26: error: called object is not a function or function pointer
 s=a1*10(3-1)+a2*(3-2)+a3*10(3-3);
                          ^~
/in/foo.c:7:12: warning: format '%f' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
 printf("%.0f",s);
            ^