/in/foo.c: In function 'main':
/in/foo.c:9:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d %d",n,m);
          ^
/in/foo.c:9:13: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'int' [-Wformat=]
  scanf("%d %d",n,m);
             ^
/in/foo.c:10:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d %d",x1,x2);
          ^
/in/foo.c:10:13: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'int' [-Wformat=]
  scanf("%d %d",x1,x2);
             ^
/in/foo.c:11:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int' [-Wformat=]
  scanf("%d %d",y1,y2);
          ^
/in/foo.c:11:13: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'int' [-Wformat=]
  scanf("%d %d",y1,y2);
             ^
/in/foo.c:13:6: error: 'i' undeclared (first use in this function)
  for(i=0;i=<l1;i++)
      ^
/in/foo.c:13:6: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:13:12: error: expected expression before '<' token
  for(i=0;i=<l1;i++)
            ^
/in/foo.c:15:7: error: 'j' undeclared (first use in this function)
   for(j=1;j=<l2;j++)
       ^
/in/foo.c:15:13: error: expected expression before '<' token
   for(j=1;j=<l2;j++)
             ^
/in/foo.c:17:4: error: 'x' undeclared (first use in this function)
    x=x1+2*i+j;
    ^
/in/foo.c:18:7: error: 'y' undeclared (first use in this function)
       y=x2+i+2*j;
       ^
/in/foo.c:12:19: warning: unused variable 'l2' [-Wunused-variable]
  int l1=(y1-x1)/2,l2=(y2-x2)/2;
                   ^~
/in/foo.c:12:6: warning: unused variable 'l1' [-Wunused-variable]
  int l1=(y1-x1)/2,l2=(y2-x2)/2;
      ^~