Comparing two integers without logical, relational or bitwise operators
That seems a fine solution. Some minor suggestions:


Instead of spelling out relationship as {'&lt;', '=', '&gt;'}, you could use simply "&lt;=&gt;"
Instead of printing a, the relation and b in separate statements, it will be more readable to print in a single printf
The expression !!(a/b) - !!(b/a) evaluates to -1, 0, 1, commonly returned by a cmp function. If you give the expression a name by putting it in a variable, that will ring a bell with many readers and make it easier to understand.


Something like this:

unsigned a, b;
scanf("%u %u", &amp;a, &amp;b);

int cmp = !!(a/b) - !!(b/a);
char relation = "&lt;=&gt;"[cmp + 1];
printf("%u %c %u\n", a, relation, b);