I am having trouble implementing a 3 dimensional array whose memory is dynamically allocated.


I am trying to think of it in terms of pointers but I am missing something conceptually because I don't quite understand how the computer handles pointers to other pointers inside of arrays

Right now here is what I have been working with:

You allocated memory for size1, size2 and size3 but never fill it with numbers.

Furthermore you dont need to allocate 2*sizeof(int)

malloc(sizeof(int)) is sufficient, since the sizes only contain one integer:



Then I can't really follow what you try to do

The array declaration should be something like this:



The definition of the array has to be somewhere:



This is a normal dynamic array. There are possibilities to get an array of pointers too.
Maybe you should be more specific

This post was edited by dipdipdip on Dec 12 2012 03:32pm

All right so it's kind of working but when the loop to print runs it prints all 0's.



This post was edited by Nom_Nomz on Dec 12 2012 05:56pm

I fixed it! had to remove that asterisk from the declaration of testarray my mistake

Damn now i am having trouble on the syntax to pass it to a function >.<

This post was edited by Nom_Nomz on Dec 12 2012 06:28pm

how is that hard.



pass it lik so


better yet iirc you can remove the asterisks from the sizeX variables and just pass the integers to the function.

This post was edited by AbDuCt on Dec 12 2012 06:58pm

that won't work because the array being passed is not o type float * but rather of the type it is initialized as the compiler spits out all kinds o problems when I try the way you posted because that was what I was trying to do earlier

this is where I am at the moment

sorry for all the space it does something weird when i post it on forums

So does this work as you intended?!

It worked up until I had to pass the array to a function, but now I realize the instructor wants the memory allocated for the set size not the set size itself allocated which now I am having problems again the fp won't read into the array anymore.

#include <stdio.h>

#include <stdlib.h>



#define SIZE_1 11

#define SIZE_2 4

#define SIZE_3 5


void avgStuClassGrade(float* [SIZE_1][SIZE_2][SIZE_3]);

void avgGradeClass(float [SIZE_1][SIZE_2][SIZE_3]);

void avgGradeStuAllClass(float [SIZE_1][SIZE_2][SIZE_3]);



int main() {

int v, x, y, z;

FILE *fp;

fp = fopen("ExamGrades.txt", "r");

float* grades[SIZE_1][SIZE_2][SIZE_3];

for (x = 0; x < 11; x++) {

for(y = 0; y < 4; y++) {

for(z = 0; z < 5; z++) {

grades[x][y][z] = malloc(sizeof(float));

}



}



}


//do {
for (x = 0; x < 11; x++) {

for(y = 0; y < 4; y++) {

for(z = 0; z < 5; z++) {

fscanf(fp, "%f", grades[x][y][z]);
printf("This is the first grade on the list: %.2f\n", grades[x][y][z]);

}

}

}

//}while ((v = fgetc(fp)) != EOF);

fclose(fp);

//avgStuClassGrade(grades);

//avgGradeClass(grades);

//avgGradeStuAllClass(grades);

return 0;
}


/*

void avgStuClassGrade(float* gradesF[SIZE_1][SIZE_2][SIZE_3]) {

float sum = 0;

float avg = 0;

int x, y, z;

for (x = 0; x < 11; x++) {

for(y = 0; y < 4; y++) {

for(z = 0; z < 5; z++) {

if (z == 4) {

sum = sum + *gradesF[x][y][z];

avg = sum / z;

printf("The average for student %d in subject %d is %f.\n", x, y, avg);

sum = 0;

}

else {

sum = sum + *gradesF[x][y][z];

}

}

}

}

}

*/

code brackets man...