Is it possible to read [1,2,3] as an input in c++?

Question

I am trying to read [1,2 3] as an input in c++ but not able read it. I am printing the size of the vector after input bit it is showing 0 only. How to read this type of input or any arbitrary input format in c++?
https://code.sololearn.com/cmcNko40dS2g/?ref=app

Answer 1

In the very first iteration, you try to read '[' as an integer as part of the condition, before the if statement becomes effective. Since '[' can not be interpreted as an integer, the internal failbit of the stream is set, which in turn causes the loop to exit immediately. As a consequence, the vector will be empty.
Here is just one idea to solve the issue by ignoring the unwanted characters:

https://code.sololearn.com/c5GBEJ42vT6q/?ref=app

Answer 2

Inspired from Shadow's and Martin's solution

https://code.sololearn.com/cZXm0yDMS6bx/?ref=app
https://code.sololearn.com/cUxU3S10zuiy/?ref=app