/in/foo.c: In function 'main':
/in/foo.c:15:12: error: expected expression before ')' token
   putchar(*);
            ^
/in/foo.c:20:25: error: expected expression before ')' token
   if (i != 0){ putchar(*); }
                         ^
/in/foo.c:22:3: error: 'ch' undeclared (first use in this function)
   ch++;
   ^~
/in/foo.c:22:3: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:31:12: error: expected expression before ')' token
   putchar(*);
            ^
/in/foo.c:36:26: error: expected expression before ')' token
   if (i != 0) { putchar(*); }
                          ^
/in/foo.c:5:13: warning: unused variable 'k' [-Wunused-variable]
  int n, i,j,k;
             ^