/in/foo.cc:1:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
/in/foo.cc:3:9: error: #include expects "FILENAME" or <FILENAME>
 #include
         ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:13:33: error: 'scanf' was not declared in this scope
 scanf("%ld%ld%ld%ld",&a,&b,&c,&d);
                                 ^
/in/foo.cc:15:41: error: 'sqrt' was not declared in this scope
 printf("%.3lf\n",DIST(0-a,sqrt((double)b),0-c,0-sqrt((double)d)));
                                         ^
/in/foo.cc:5:58: note: in definition of macro 'DIST'
 #define DIST(x1,y1,x2,y2) sqrt(((x1)-(x2))*((x1)-(x2))+((y1)-(y2))*((y1)-(y2)))
                                                          ^~
/in/foo.cc:5:79: error: 'sqrt' was not declared in this scope
 #define DIST(x1,y1,x2,y2) sqrt(((x1)-(x2))*((x1)-(x2))+((y1)-(y2))*((y1)-(y2)))
                                                                               ^
/in/foo.cc:15:18: note: in expansion of macro 'DIST'
 printf("%.3lf\n",DIST(0-a,sqrt((double)b),0-c,0-sqrt((double)d)));
                  ^~~~
/in/foo.cc:5:79: error: redeclaration of '<typeprefixerror>sqrt'
 #define DIST(x1,y1,x2,y2) sqrt(((x1)-(x2))*((x1)-(x2))+((y1)-(y2))*((y1)-(y2)))
                                                                               ^
/in/foo.cc:15:18: note: in expansion of macro 'DIST'
 printf("%.3lf\n",DIST(0-a,sqrt((double)b),0-c,0-sqrt((double)d)));
                  ^~~~
/in/foo.cc:15:41: note: previous declaration '<typeprefixerror>sqrt'
 printf("%.3lf\n",DIST(0-a,sqrt((double)b),0-c,0-sqrt((double)d)));
                                         ^
/in/foo.cc:5:58: note: in definition of macro 'DIST'
 #define DIST(x1,y1,x2,y2) sqrt(((x1)-(x2))*((x1)-(x2))+((y1)-(y2))*((y1)-(y2)))
                                                          ^~
/in/foo.cc:15:65: error: 'printf' was not declared in this scope
 printf("%.3lf\n",DIST(0-a,sqrt((double)b),0-c,0-sqrt((double)d)));
                                                                 ^