/in/foo.c: In function 'main':
/in/foo.c:4:27: error: 'i' undeclared (first use in this function)
    4 |         int n,a,b,c,e,j=0;i=0;
      |                           ^
/in/foo.c:4:27: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:34:17: error: 'd' undeclared (first use in this function)
   34 |                 d=((n%1000)%100)%10;
      |                 ^
/in/foo.c:36:51: error: 'J' undeclared (first use in this function)
   36 |                 printf("%d\n,%d ,%d ,%d ,%d\n,%d",J,a,b,c,d,i);
      |                                                   ^