General 3 Dim Array Memory Allocation Question

[itdamon]

Hi,

I have a general memory allocation question, this topic came up at work and everyone has different answers.

If I have an integer array of 3 dimensions, with each dimension having 1000 elements, on a 32 bit system, how many bytes does it take to create this array?

I'm thinking it would be 1000 * 1000 * 1000, (1,000,000,000 spaces? ...this can't be right! 4 bits for an integer would be like 4 billion bytes!)

Just kinda curious.

 

[itdamon]

Oh, I'm using the sizeof function to try and evaluate this question, the compiler tells me one thing, and my brain is trying to tell me something else. I think I'm missing something here.

#include <stdio.h>

int intArray[100];

/* Not sure how big array size is, so I'll use long data type to be safe. */

long int_3D_100_Array[100][100][100];

long int_3D_1000_Array[1000][1000][1000];

void main(void){

printf(&quot;Size of int data type = %d bytes.\n&quot;, sizeof(int));

printf(&quot;Size of long data type = %d bytes.\n&quot;, sizeof(long));

printf(&quot;Size of a int[100] arrary = %d bytes.\n&quot;, sizeof(intArray));

printf(&quot;Size of a int[100][100][100] array = %d bytes,&quot;, sizeof(int_3D_100_Array));

printf(&quot; or %d Kb.\n&quot;,(sizeof(int_3D_100_Array)/1000));

printf(&quot;Size of a int[1000][1000][1000] array = %d bytes,&quot;, sizeof(int_3D_1000_Array));

printf(&quot; or %d Kb.\n&quot;,(sizeof(int_3D_1000_Array)/1000));

}

 

[gasingh]

of course you are right 1000 * 1000 * 1000 *sizeof(int) is the result.
i.e. 4 * 1000 *1000 *1000.