Programming education

Only course I''ve had was pascal in A-Level computing which was pointless as I didn''t learn anything. Which concepts are you stuck on there''s gotta be at least one person here who can help you.

I can''t exactly remember, it''s been that long since I actually looked at the problem. This shows you how discouraged I''ve become. Arrays and calling them is where I left off. I''ll hafta sift through my notes to remember exactly what the problem is. My primary sources are "C for Dummies (both volumes)" and "The Complete C++ Reference". I cross-referenced the two and found it quite effective. Until I got stuck. Maybe it''s a brain fart, I dunno. I just feel kinda defeated. I need a kick in the pants. Or the head. Any advice on calling arrays, though?

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Now, THERE''s your crap post.

I had the basic courses you''re forced to take on the way to BS in Computer Science, but I found that I learned more from my personal projects and books. (Like many CS students, I didn''t appreciate the material presented in class, and did just enough to get the grade I wanted. The classes might have been more beneficial if I hadn''t been stuck in that mindset.)

What do you mean by calling arrays? Declaring them?

Jesse Chounard
jesse@k-isilabs.com

What exactly do you mean by calling arrays?

Well I''ll just explain arrays. An array is a series of variables that are generally next to each other in RAM. In XC they are declared like like this

variabletype variablename[sizeofarray];

eg int Array[15]; //declares an array of 15 integers

You can initialize them at declaration like this:

int Array[3] = {1,2,3};

Accessing individual variables in arrays is easy to do :

printf("%d",Array[2]); //would output 2 using array above

The number you put in the square brackets is the index of the variable you wish to access.

You can also create multidimensional arrays. eg

floats array2[2][2];

That creates a 2x2 array of floats. You access it the same way you do with a single dimensional array eg.

array2[1][2]; willl access the value stored at 1,2

You can also have dynamically allocated arrays

int *Pointer; //creates a pointer needed for memory allocation

Pointer = (int*)malloc(5); //creates an array of five integers

The (int*) is a cast that converts mallocs return to an integer value (malloc returns void).

quote:

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Original post by crazy-vasey
Pointer = (int*)malloc(5); //creates an array of five integers

The (int*) is a cast that converts mallocs return to an integer value (malloc returns void).

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Almost right..

That would allocate 5 bytes. You need:
Pointer = (int*)malloc(5 * sizeof(int));

Or the C++ way:
Pointer = new int[5];

Jesse Chounard
jesse@k-isilabs.com

Thanks for the help. I think the problem I was running into was this: it seemed that the examples the book used were calling on a single interger out of the array with a function. Something like...

cheers()[4];

when the array was originally declared to be 15 intergers long:

array[15]={1,2,3...}

I''m probably not remembering it correctly, and I don''t have the book in front of my right now either. But it seems like that was my problem. Thanks for the encouragment, at any rate. It started to click and I was enjoying it, then I hit this roadblock. Ug.


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Now, THERE''s your crap post.

That code could definitely work, if the function is returning a pointer.

Something like:

#include<stdio.h> int array[20]; int* function(void) { int *pointer; pointer = array; pointer[2] = 25; return pointer; } int main() { int returned; returned = function()[2]; printf("%d\n", returned); return 0; }

I hope that''s not confusing.. I was simply trying to illustrate that a pointer and single-dimensional array are pretty much interchangable.

Jesse Chounard

oops I make that mistake all the time.