Introduction - If you have any usage issues, please Google them yourself
The basic number crunching C# example, perform the addition of two numbers, subtraction, back together, after subtracting the result of instantiating the class object that defines an infinite loop to loop the input data, records arithmetic symbols to arithmetic symbols conditions to judge, to determine whether the plus sign to determine whether the minus sign, does not meet all of the above cases, the basic addition and subtraction.