TI-BASIC:Number Or String

Routine Summary

Determines whether an input is a number or string.

Inputs

Ans - the number or string to examine

Outputs

Ans - 1 if the input is a number, 0 if it is a string

Variables Used

A, B [,∟A, ∟B if input is a string]

Calculator Compatibility

TI-83/84/+/SE Author

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routine.zip

: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.