Reference a struct member variable

[Chris Losinger]

manoharbalu wrote:

Now I want the sim1->IV to exactly point to sim2->RIV

so you need to do this:

struct test1
{
float *IV;
...

and when you create a test1 object, you have to set the pointer to a test2's RIV array:

sim1 = new test1();
sim2 = new test2();
sim1->IV = &sim2->RIV[0];

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[CPallini]

manoharbalu wrote:

Now I want the sim1->IV to exactly point to sim2->RIV
and sim1->NENTH to exactly point to sim2->RNENTH.

If you need a pointer then use a pointer:

struct test1
{
float * IV;
//...
float * NENTH;
//...
};
//...

test1 *sim1;
test2 *sim2;

sim2 = new test2();
sim1 = new test1();
sim1->IV = sim2->RIV;
sim1->NENTH = sim2->RNENTH;

Veni, vidi, vici.

[Lost User]

You have something over 20,000 floats in each of your structures; are you really sure this is what you want?

Programming is work, it isn't finger painting. Luc Pattyn

[Aescleal]

- Replace test1::IV with a pointer to float - Replace test1::NENTH with a pointer to float - Add a constructor for test1 that takes a test2 by reference and set up the pointers in there As Richard said are you sure you want that size of object kicking around? And are you sure you want one object to interfere directly with the internals of another object? That usually leads to tears and breaking an object's invariant. Cheers, Ash Edit as I forgot the important bit in italics

[manoharbalu]

Yes I need that.

[TomasRiker2]

Here you see that arrays and pointers are not quite the same although they behave almost similarly. You can't change the address of an array once it was created.

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[Albert Holguin]

That's a great question...

[Lost User]

yeah, and he will probably declare them on the stack.....

============================== Nothing to say.

[Lost User]

As others suggest, you need pointers, but if you really have common data shared between two structs then take it out of them and put it in a third struct.

============================== Nothing to say.

[Aescleal]

A far better way of doing things than I suggested. Cheers, Ash

[Stefan_Lang]

I suggest you go with the suggestion of Erudite_Erik. I took the liberty to put it into code:

struct testsub
{
float IV [300];
float NENTH [600];
};

struct test1
{
// constructor:
test1(float* iv, float* nenth)
: IV(iv), NENTH(nenth) // this initializes the pointer variables
{
}

float\* IV;
char FAIL \[200\];
char FD \[600\];
float\* NENTH;
float NKVAL \[30\]\[600\];
float NLEVEL \[600\];
int COUNT;
int CTIME;
};

struct test2
{
// constructor:
test2(float* iv, float* nenth)
: RIV(iv), RNENTH(nenth) // this initializes the pointer variables
{
}

float\* RIV;
float RXX \[100\];
char RFAIL \[200\];
char RFD \[600\];
float RTB \[50\];
float\* RNENTH;
char GCD \[200\];
float RNKVAL \[30\]\[600\];
char MTBD \[600\];
float RNLEVEL \[600\];
int RCOUNT;
int RCTIME;

};

void foo()
{
// allocate objects
struct testsub * sub = new testsub();
struct test1 *sim1 = new test1(sub->IV, sub->NENTH);
struct test2 *sim2 = new test2(sub->IV, sub->NENTH);

// now do some stuff
// ...

// now release memory
delete sim2;
delete sim1;
delete sub;

}