Double* modification for input

[gugge444]

I created a 1d array using the trick double* x = new double[var]; which seems to be the only way of creating an array with a variable size. However, I now need to use the parts of x --> (x[1], x[2], ..., x[i]) in a function that requires a double input, and I cannot do that with a double*.

Is there a way of solving this without entering the source code and trying to change the input method, or rather, is there a way of turning a double* to a double, or better yet, create a double with a variable input?

Thanks in advance.

[EssGeEich]

When a function takes a double, you can only give it a single double, not more than one at once.
For examples:

x[0] // is the first element into x
x[1] // is the second ...
x[var-1] // is the last
x[var] // FAILURE! Don't Do This! 

[gugge444]

Thank you, that is accurate, but not what I was asking. I know I formulated the question poorly, sorry about that.

What I meant to ask is: when I attempt to make the size of a double[] using a variable, the error:
expression must have a constant value
appears. The way to bypass this is to make the double[] into a double*[]. However, this type is not compatible with a function I want to run it through.

So my question is: do I have to rewrite the function, or is there a way of bypassing this error?

[EssGeEich]

Sorry but, Have you tried passing it normally?
Let me explain you this:

void FunctionThatTakesDoubleArray(double[] Data) {}
// ...
double StaticSized[5];
double * DynamicSized = new double[5];
FunctionThatTakesDoubleArray(StaticSized); // Valid
FunctionThatTakesDoubleArray(DynamicSized); // Also Valid, Same Effect 

If yet I didn't answer correctly, could you make an example, posting a little code snip maybe?

[maeriden]

is there a way of turning a double* to a double

Dereference it

double* x = new double[var];
// Initialize array elements
double d = *x; // It's the same as doing d = x[0]
double d2 = *(x + 2); // Same as x[2] 

create a double with a variable input?

Not sure what you're asking here

However, I now need to use the parts of x --> (x[1], x[2], ..., x[i]) in a function that requires a double input, and I cannot do that with a double*

If your function works with a single double at a time, just pass it using an index

 void function(double);

// In main()
function(x[0]);

I'm guessing you just started dealing with pointers. If you need help understanding what's going on feel free to ask