Array Elements as Function Arguments in XC

[markseel]

Hi All,

Given a function like this:

void multiply_by_2( int& element ) { element *= 2; }

And an integer array:

int values[4] = {1,2,3,4};

I'd like to call the function using one of the array elements as the function argument.
Something like this:

multiply_by_2( &values[1] );

But that's invalid syntax for XC. How do I pass (by reference) an element in the array to the function 'multiply_by_2'?

[richard]

Hi All,

Given a function like this:

void multiply_by_2( int& element ) { element *= 2; }

And an integer array:

int values[4] = {1,2,3,4};

I'd like to call the function using one of the array elements as the function argument.
Something like this:

multiply_by_2( &values[1] );

But that's invalid syntax for XC. How do I pass (by reference) an element in the array to the function 'multiply_by_2'?

For reference arguments the address is implicitly passed, so you can just write:

Code: Select all

multiply_by_2(values[1]);

[markseel]

Makes sense - thanks for posting!

So given this function:

void multiply_3_elements_by_2( int values[] )
{
values[0] *= 2;
values[1] *= 2;
values[2] *= 2;
}

And an integer array:

int values[4] = {1,2,3,4};

How do I pass the array such that the last three elements are used?
I want to pass a reference/pointer to the array element existing at a non-zero offset.

In 'C' I'd do something like this:

multiply_3_elements_by_2( array + 1 );
... or ...
multiply_3_elements_by_2( &array[1] );

How do we do this in 'XC'?

[richard]

How do I pass the array such that the last three elements are used?
I want to pass a reference/pointer to the array element existing at a non-zero offset.

This isn't possible in XC. Instead you have to pass the array and the offset to start at as separate arguments. Having a way to pass a slice of an array is something that would be useful and it is something we will consider when we next make changes to the the language.