Modify the value of a variable from a function

Unity Engine
1

Hi,

I’m trying to create a function where if I pass an int variable to it, it changes it’s value. I tried the following but it just changes “var” inside the function but doesn’t change the value of “variable1” and “variable2”. Is there any way to do this?

    int variable1;
    int variable2;

    void Function(int var) {
        var = 1;
    }

    void Start() {
        Function(variable1);
        Function(variable2);
    }

How could I create a function that actually changes the value of “variable1” and “variable2” to 1 without creating multiple functions that contain the name of these variables?

Thanks!

2

Because var is just declared inside that function. You can do something like this though:
int Function(int var){
var =1;
return var;
}
Meaning you will return the value of what you set it to, so you can do something like variable1 = Function(variable1);

3

Here are 3 ways you could do what you’re trying to achieve.
Note that you probably shouldnt use keywords like that when defining variables ‘var’ etc. Consider at a glance you might not know what it is right away, perhaps consider naming it ‘num’ instead. :wink:

// 1) 'ref'

// ref keyword means "pass by reference" - edits
// made in this function affect the actual variable
int someNum = 5;
AddOne(ref someNum);
// someNum now = 6

void AddOne(ref int i)
{
    i++;
}

// 2) 'return'
// As stated you could return the value instead
int someNum = 5;

// Call AddOne, passing in our someNum value and set the value
// that AddOne returns back into out someNum variable.
someNum    = AddOne(someNum);

int AddOne(int i)
{
    // You could return right away by doing something like
    // return ++i;
    // however for verbosity, im not in this example.
    i += 1;
    return i;
}

// 3) 'Extension method'
int someNum    = 5;

// I cant think of how to correctly say what an extension method
// actually is so heres a link:
// https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods
// https://www.dotnetperls.com/extension
someNum.AddOne();

public static int AddOne(this int i)
{
    i += 1;
    return i;
}
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