C#•2y ago

✅ Mathematical Expressions

Hi, for my university assignment, I am required to add complex expressions alongside my variables. The complex expression is just mathematical stuff. an example is - var size 10 (this creates a variable with the value of 10.) size = size * 3 (this should overwrite the value of size to 30.) i need some help to do this. when i remove the line - size = size * 3, it draws the shape. https://hastebin.com/pivuwabelo.csharp

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31 Replies

Thinker•2y ago

To be clear, is this like a language you have to implement?

MaGiiKxOP•2y ago

basically yes. its to draw shapes this is basically like a little environment for kids to draw shapes using commands

Angius•2y ago

Making your own version of Logo, basically?

MaGiiKxOP•2y ago

i think so

Thinker•2y ago

What is it you actually need help with? Drawing the circle? Parsing?

MaGiiKxOP•2y ago

no, so my variable already works when i type in

var size 10
circle size

var size 10
circle size

it will draw the circle with the variable value

Angius•2y ago

So it's assigning new values to variables that doesn't work

MaGiiKxOP•2y ago

what i want to do now is,

c 
when users type in 
var size 10
size = size * 3
circle size

c 
when users type in 
var size 10
size = size * 3
circle size

I want it to overwrite the current value of size (10) and update it to (30) and then draw the circle with the radius of 30

Thinker•2y ago

So... what kind of system do you have? I assume you're using a dictionary for variables?

MaGiiKxOP•2y ago

im not using a dictionary ill show you

 private void DeclareVariables(string name1, string value1, string name2, string value2)
        {
            // Check if the variables are valid and store them if they are.
            variableCheck(name1, value1, name2, value2);
        }










        private int GetVariableValue(string name)
        {
            // Iterate through the variableName array.
            int i = 0;
            while (i < variableName.Length)
            {
                // If the current element of the variableName array is equal to the name parameter,
                // return the corresponding element of the vParams array.
                if (variableName[i] == name)
                {
                    return vParams[i];
                }
                i++;
            }
            // If the name parameter is not found in the variableName array, return -1.
            return -1;
        }

 private void DeclareVariables(string name1, string value1, string name2, string value2)
        {
            // Check if the variables are valid and store them if they are.
            variableCheck(name1, value1, name2, value2);
        }










        private int GetVariableValue(string name)
        {
            // Iterate through the variableName array.
            int i = 0;
            while (i < variableName.Length)
            {
                // If the current element of the variableName array is equal to the name parameter,
                // return the corresponding element of the vParams array.
                if (variableName[i] == name)
                {
                    return vParams[i];
                }
                i++;
            }
            // If the name parameter is not found in the variableName array, return -1.
            return -1;
        }

Thinker•2y ago

What is variableName and vParams?

Akseli•2y ago

use a dictionary instead of array to store variables

MaGiiKxOP•2y ago

on the command line, it will split whenever it detects a space. parameter[0] will be the variable name (in this case it would be size) vparams is just the values of the variables

Thinker•2y ago

Assuming you don't have scopes, a simple dictionary would work fine

Angius•2y ago

So you store names and values in separate arrays...? Why? Use a dictionary Or a list of classes or something

MaGiiKxOP•2y ago

i was following how my lecturer did it in his examples, this looked like the easiest way

Angius•2y ago

The only time when I see people store related values inside of unrelated arrays is when they're clueless about OOP So you either misunderstood or misapplied what the lecturer did, or they have no business teaching

MaGiiKxOP•2y ago

lmaoo i have no idea so i should change the code to dictionary?

Thinker•2y ago

If you were to use a dictionary, you could literally just do

variables[variableName] = variableValue;

variables[variableName] = variableValue;

MaGiiKxOP•2y ago

okay so suppose i change it to a dictionary, how would i do the complex expressions?

Thinker•2y ago

Are you receiving the expressions as a plain string?

MaGiiKxOP•2y ago

so when user types it in the command line it will be a string, it is then split and parsed and stored in their correct parameters

Thinker•2y ago

have you already parsed the expression into something like a syntax tree?

MaGiiKxOP•2y ago

no, so i need to add the expressions like + - * / into my code all it parses right now is just the numbers theres no mathematical side to it

Thinker•2y ago

I don't know what your lecturer wants, but if you wanna parse expressions with precedence and whatnot there's a couple ways. The first would be to write a simple parser, the second would be one of the several math expression algorithms out there. What's the lecture/course about?

MaGiiKxOP•2y ago

the module is advanced software engineering this is just one of the module its just developing a mini ide to draw shapes using commands

Angius•2y ago

If there's "advanced" in the name, chances are it does expect you to parse it into some AST and process that A parser + an interpreter

Thinker•2y ago

In which case, check out one of these two https://en.wikipedia.org/wiki/Shunting_yard_algorithm https://craftinginterpreters.com/parsing-expressions.html The second link is about implementing an abstract syntax tree (AST) and an expression parser.

MaGiiKxOP•2y ago

ive heard of shunting yard algorithm hi again, will you guys be able to help me with something else?

MaGiiKxOP•2y ago

will you be able to help me with this

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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✅ Mathematical Expressions