/in/foo.c: In function 'main':
/in/foo.c:4:17: error: lvalue required as left operand of assignment
  scanf("%b%b",&a=123,&b=500);
                 ^
/in/foo.c:4:24: error: lvalue required as left operand of assignment
  scanf("%b%b",&a=123,&b=500);
                        ^
/in/foo.c:6:10: warning: unknown conversion type character 'b' in format [-Wformat=]
 printf("%b\n",sum);
          ^
/in/foo.c:6:8: warning: too many arguments for format [-Wformat-extra-args]
 printf("%b\n",sum);
        ^~~~~~