How do i check if input is always an int?

Question

I have a method

Answer 1

For C++
use header ctype.h and function isdigit(variable)

Answer 2

you can convert to int with to_i method

a = gets.to_i

Answer 3

hey thanks guys sorry phone died.

I want to check if what the user gives me is text then give an error and if it's an integer then run it through an if statement

Answer 4

temp=gets.chomp
bool = temp .is_a ? integer
if bool
if temp < 20
do
else do