Main.c: In function 'main':
Main.c:15:13: error: 'step' undeclared (first use in this function)
   15 |             step=abs(x1-x2)+abs(y1-y2);
      |             ^~~~
Main.c:15:13: note: each undeclared identifier is reported only once for each function it appears in
Main.c:15:18: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
   15 |             step=abs(x1-x2)+abs(y1-y2);
      |                  ^~~
Main.c:3:1: note: include '<stdlib.h>' or provide a declaration of 'abs'
    2 | #include<math.h>
  +++ |+#include <stdlib.h>
    3 | int main()