vectors in c?

[Unregistered]

okay heres my problem

i need to write a small program using the vector data structure but i am unsure how to set up the structure itself, i can manage queues and stacks without too much difficulty, but the vector eludes my small mind

i dont want anyone to write my program, just some hints and tips will be great

heres what i think i need

struct datatype
{
char errorMessage[27];//used to store each message
};

struct vectorTable
{
datatype data;
};

.
.
.

int main(void)
{
datatype data[10];//maximum messages required
.
.
.
}

and so on

any help will be appreciated

thanx

[quzah]

You will have to fake using a vector in C. To do so, use a linked list. Actually, as we were discussing in another tread, you could actually kind of use a vector. Not really. According to the C99 (according to someone else on this board) you can use sized arrays. However, this will be compiler specific! If you have an older compiler, this is invalid. If you have a new one, it isn't:

int x;
puts("Enter the size of the vector"
scanf("%d", &x);
puts("Creating vector.");

struct myStruct myVector[x];



Will that work for you?

Quzah.

[pinko_liberal]

very few compiler manufacters seem to be keen on implementing C99

[QuestionC]

Umm... sorry guys, but could someone fill me in on what a vector is, because I'm thinking...

struct vector
{
 int x;
 int y;
}

Sometimes the ties between math and programming are not so helpful, eh?

[quzah]

There is a "vector" class in C++ and an implementation in Java. Basicly, and I haven't used them myself, so I may be off, it's like a resizable array. It has built in features (members) to tell you the size, to add to it, etc.

It's pretty much like:

Vector myVector[20];
for(x=0; myVector.Size();x++) myVector[x] = somenumber;

myVector.resize( 30 );

for(x=21;x<myVector.Size();x++) myVector[x] = somenumber;

Kinda like that. That's a fair example I believe. Again, I haven't personally used them..actually that's not quite true, I did a passing glance/bit of code at them in C++ once..so I'm not an expert on them.

Quzah.

[pinko_liberal]

do you mean two dimensional space , three dimensional space etc .

for eg., you could represent the R^3 as

struct point_3d
{
double p[3];
};
p[0], p[1] , p[2] representing the x,y and z axes in your favorite order,
there is no inbuilt support for these types , in C99 there is inbuilt support for complex numbers , but I do not know much about it .
You will have to write your own functions for manupulating them
eg.

double norm_3d(const struct point_3d *pt)
{
      double d=0.;
      int i;  
      for(i=0;i<3;i++) d += (pt->p[i])*pt->p[i];
      return sqrt(d);
}

[quzah]

The "vector" I'm talking about can be of any type (if I remember correctly). Basicly, think of it as an array which you can resize at any time. That's pretty much what a C++/Java "Vector" is.

Quzah.