ASP.NET Core 3.1 String Calculator
This calculator can take up to two numbers, separated by commas, and will return their sum.
For an empty string it will return 0
It accepts newline characters in place of a comma, as a delimiter. For example “1\n2,3” returns 6. However "1,\n2” is invalid.
You can also specify your own delimiters by beginning the input with //
//\n12 will return 3
//%\n12%3 will return 6