I tried code evil function you can see
here you define the keywords and if matches it search for the number after that it excite function define in the code.
A basic way:
1) Read the input
2) Divide the input in logical pieces (numbers and operators)
3) Use something for order all operations from their precedence and associativity (at example 2+3*5 is equals 3*5 = 15 + 2= 17) if do you want (usually is made by using a tree ds)
4) perfom the operations
Sonic not necessarily, if you create a lexical analyzer. you can calculate multiple mathematical expressions in one line with the use of stacks by changing them into a postfix notation.
KrOW explained a part of how this was done with the PEDMAS method to correctly structure the expressions.
this is usually how calculators and machines calculate multiple expressions.
here is a link on how it's done.
I did a similar calculator some days ago in c++
The logic is pretty simple, when you perform a calculation the result will be affected by the next calculation and so on...
Example: (2*3+5) 2*3=6, 6+5=11...
Here's the code anyway:
I don't know why this in sololearn doesn't work, but if you use others ide, it works