How to use string.substr() function?

Question

I want to make a program that will read some number in string format and output it like this: if the number is 12345 it should then output 12 23 34 45 . I tried using the su

Answer 1

substr(i,j) means that you start from the index i (assuming the first index to be 0) and take next j chars. It does not mean going up to the index j.