TI-BASIC:Number Or String
:DelVar AFor(B,1,1 :Ans->A :Ans->B :A=B
If Ans is a string, it is stored to ∟A and ∟B. A remains 0, B remains 1, and A=B returns false. If Ans is a number, it is stored into both A and B, thus A=B returns true.
The For( command is used to avoid updating Ans. If this routine is used in a larger program and the input can be stored into a more permanent variable, For(B,1,1 can become 1->B. If this is not possible, the For( statement should have an End added.