errored program

can someone look at my code and tell me what I'm doing wrong here.

I keep getting these errors.
error C2057: expected constant expression
error C2466: cannot allocate an array of constant size 0
error C2133: 'array' : unknown size

I have the following declared in the program and assume that it should work.

Code:

---

const int SIZE=99;

int array[SIZE],

---

according to my text book this syntax is correct.

In 'old style' C at least you can't even use a const to specify
the size of an array. You have to do it like this:

Code:

---

#define SIZE 99
...
int array[SIZE]

---

It's a pain, but there you go... I'm not sure if this is still the case
for c99.

Don't use void main. Try to be more consistent with your indentation.

how would you pass a #define to function?
do you have to pass the size of the array with the array to the function?

> how would you pass a #define to function?

Code:

---

#include <stdio.h>

#define SIZE 99

int print_number(int number);

int main(void)
{
    print_number(SIZE);
    return 0;
}

int print_number(int number)
{
    printf("%d", number);
    return 0;
}

---

You don't pass the #define to the function you use it like a global
variable. I suppose you could do something like:

Code:

---

int array[SIZE];
unsigned int siz = SIZE;

foo(array, size);

---

Alternatively, if you need to set SIZE at run time use malloc()

Code:

---

void foo (unsigned int size)
{
  int * array;
  ...
  array = malloc(size * sizeof(*array));
  ...
  free(array);
}

---

I should maybe point out that I haven't looked at your program,
maybe there's some complexity there that I don't know about.

I'm new to c, but fluint (at least i think) in c++.
The transition is confusing.

I'm used to passing arrays in c++.
This involves passing the array and a const int for the size.

Due to the errors I have received I'm assuming that this is not so for c.

If I'm reading your post correctly, I'm lead to believe that you do not need to pass a size to the function to reserve array memory.

Quote:

---

Originally posted by xviddivxoggmp3

I'm used to passing arrays in c++.
This involves passing the array and a const int for the size.

Due to the errors I have received I'm assuming that this is not so for c.

If I'm reading your post correctly, I'm lead to believe that you do not need to pass a size to the function to reserve array memory.

---

Your errors aren't to do with passing arrays to functions but declaring variable size arrays.

would this be valid?

Code:

---


#define SIZE 99;

int array[SIZE];

foo(array);

---

or how about this

Code:

---


int * array;

array = malloc(size * sizeof(*array));

foo(array);

---

>would this be valid?
No. The semicolon at the end of your define directive will wreak havoc after preprocessing.

>or how about this
No. size is undefined in the code given. Provided size exists and has a valid value, yes, it would work.

You might want to pass the array lengths to foo() (depending on what kind of array you have).

as for passing the length of the array.
If i'm using a single demensional integer array, and not using the size for anything in the function, should i pass the size or length.
I feel it as inconsiquential to the program.

If you don't process the array in a way that would require the size, then you have no reason to pass it as an argument. Though I can't think of too many situations where this would be acceptable. Most of the time you need access to the array's size.

It compiles finally, but know my logic is generating duplications of the answer. Can someone look to see if it is something stupid I missed. I'm in the middle of tracing it now, but if someone could help I would much appreciate it.

I'm not sure if this works, but I'm w/o a compiler to check.
can someone check this to see if it works.

(1) does it compile. if not what errors does it print?
(2) does it print acceptable output?

Goal:
All even numbers 2-50 can be represented by the sum of two prime numbers.

2=1+1
4=3+1
...

[edit1]
my trace has resolved the majority of the issues.
[/edit1]