How to detect if a variable has changed?

Question

I have found myself wanting to do certain things in my programs only if a variable has changed. I have so far been doing something like this:

int x = 1;
int initialx = x;

...//code that may or may not change the value of x

if (x!=initialx){
    doOneTimeTaskIfVariableHasChanged();
    initialx = x; //reset initialx for future change tests
}  

Is there a better/simpler way of doing this?

Answer 1

Example:

create a variable with the same name with a number.

int var1;
int var2;

if(var1 != var2)
{
//do the code here

var2 = var1;
}

hope this help.

Answer 2

Since you want to find and perform some action only if the value changes, I would go with setXXX, for example:

public class X
{
    private int x = 1;

    //some other code here

    public void setX(int proposedValueForX)
    {
       if(proposedValueForX != x)
       {
           doOneTimeTaskIfVariableHasChanged();
           x = proposedValueForX;
       }
    }
}