How to use user defined type in other function.

Manoj7390

Hi, I have written a code in C++ which works on the "POINT" user defined type i.e. POINT = (x,y). I am giving input in int form, it is converting it into point might be using "template". I am retrieving these point from another function which is a header file of mine. Now the problem is, I am calling this function in NS-3 software/program, I am unable to convert this point form into integer. * Can i return more than one value from a function, because point has two values i.e. X and Y. Please help me out.

Lost User

Assuming you mean the POINT structure[^], you could pass it back by pointer, or pass in a pointer or reference that the called function fills in.

Use the best guess

Manoj7390

Here is my some part of my code....

int my_encrypt()

{

typedef EllipticCurve<263> ec\_t;

ec\_t   myEllipticCurve(1,1);

ec_t::Point P = myEllipticCurve[2]; cout << "some point P = " << P << ", 2P = " << (P+P) << "\n"; int a = irand(1,myEllipticCurve.Degree()-1); ec_t::Point Pa = a*G; // public key cout << "Alice' public key Pa = " << a << "*" << G << " = " << Pa << endl;**

ec_t::Point Pk = a*Pb;

ec\_t::ffe\_t c1( m1\*Pk.x() );

ec\_t::ffe\_t c2( m2\*Pk.y() );

I need to return these three values (Pa, C1, C2) into my main function.**

Lost User

Sorry, but you lost me at typedef EllipticCurve<263> ec_t;.

Use the best guess

CPallini

then change your function:

int my_encrypt(ec_t::Point * pPa, ec_t::ffe_t * pc1, ec_t::ffe_t * pc2 )
{
//...

// 'return' the values
*pPa = Pa;
*pc1 = c1;
*pc2 = c2;

return 0; // or whatever is meaningful for you
}

You may as well use the approach suggested by Richard, that is embed Pa, c1, c2 into a struct and pass the pointer to such a struct to your function.

Veni, vidi, vici.

Manoj7390

Hi.. i have used the structure to pass three different variable as shown below... int main() { struct result t1; t1 = my_encrypt(); cout << t1.pa << t1.c1 << t1.c2 <<; } struct result my_encrypt() { typedef EllipticCurve<263> ec_t; struct result { ec_t::Point Pa; ec_t::ffe_t c1; ec_t::ffe_t c2; }t; ec_t::Point Pk = a*Pb; ec_t::ffe_t t.c1( m1*Pk.x() ); ec_t::ffe_t t.c2( m2*Pk.y() ); return (t); } I am getting so many errors.. Please tell me anything wrong declaration here. Can i declare that structure as global...

CPallini

Quote:

int main() { struct result t1; t1 = my_encrypt();

Should be:

int main()
{
struct result t1 = {0};

my\_encrypt(&t1);
//..

Quote:

struct result my_encrypt() {

should be:

int my_encrypt(struct result * pt1)
{
// ...

Please note, there are other (unrelated) errors in your code.

Veni, vidi, vici.