How to split a string of an arithmetic expression?

Question

C++ / C#

You need to split the string of an arithmetic expression. For example 123+78+11 by 123, +, 78, +, 11. Can this be done through functions in the standard libraries. If on your own, how? It is desirable that numbers be converted to int/long and operands to char. C language.

Answer 1

It is also possible through the functions in the library https://habr.com/ru/post/325446/