I know two basic differences:
1.In structural induction you can use both numeric and string datatype,while in ordinary only numeric is allowed.
2.In structural there is base case and constructor case,while in ordinary there is base case ,induction hypothesis and induction step.And in structural there can be many base cases.
--> Kindly confirm if these are right and tell me more differences between structural & ordinary induction.
You are somewhat correct.
Structural induction is a more convenient form of induction used to prove results about recursively defined sets. It consists of two parts which are:
Basis Step: Show that the result holds true for all elements specified in the basis step of the recursive definition to be in the set.
Recursive Step: Show that if the statement is true for each of the elements used to construct new elements in the recursive definition, the result holds for these new elements.
In conclusion, structural induction can be used to prove that all members of a set constructed recursively have a particular property.