Array Question

If I do

Code:

#include <stdio.h>
float ave(float stu[][3][4]);
float sAve(float stu[][4]);


int main()
{
int i, j, k;
float stu[2][3][4];

for(i=0; i<2; i++){
    for(j=0;j<3;j++){
        for(k=0; k<4; k++){
            if(k==0){
                printf("Enter in the grade for student %d in subject %d", j+1, k+1);
                scanf("%d", &stu[i][j][k]);
            }else
                scanf("%d", &stu[i][j][k]);
}
}
}
printf("All Averages: %f", ave(stu));
printf("Student Averages: %f", sAve(stu));

}
float ave(float stu[][3][4])
{
float sum=0;
int i, j, k;

for(i=0; i<2; i++){
    for(j=0;j<3;j++){
        for(k=0; k<4; k++){
            sum+=stu[i][j][k];
            
}
}
}
return (sum/24);
}
float sAve(float stu[][4])
{
float sum=0, l=3, m=4;
int i, j;
for(i=0; i<2; i++){
    for(j=0;j<3;j++){
    sum+=stu[i][j];
            }
                }
return (sum/12);
                }

C:\Users\J\Desktop\gcc Lab8a.c -o Lab8a
Lab8a.c: In function 'main':
Lab8a.c:29:1: warning: passing argument 1 of 'sAve' from incompatible pointer ty
pe [enabled by default]
Lab8a.c:9:7: note: expected 'float (*)[4]' but argument is of type 'float (*)[3]
[4]'

Originally Posted by Sorinx

That doesn't help me much because my issue isn't passing the array, it's when I have a 3 dimensional array I only want to pass the 2nd and 3rd dimension to the function

Really...

It does if you think about it...

Code:

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>


#define MAX_S 10


void print_s(char (*arr2D_ptr)[][MAX_S]);


int main (void)
{


    char arr2D[2][2][MAX_S] =   {
                                    {
                                         "string 1",
                                         "string 2"
                                    }   ,
                                    {
                                         "string 3",
                                         "string 4"
                                    }
                                };


    print_s(&arr2D[0]);
    print_s(&arr2D[1]);


    return EXIT_SUCCESS;


}


void print_s(char (*arr2D_ptr)[][MAX_S])
{
    puts((*arr2D_ptr)[0]);
    puts((*arr2D_ptr)[1]);
}

1. Pass the whole thing to the function and only use the second and third dimension inside the function.
2. Create a temporary two dimensional array, copy the desired elements from the real array, and pass the temporary array to the function.

Originally Posted by Matticus

1. Pass the whole thing to the function and only use the second and third dimension inside the function.
2. Create a temporary two dimensional array, copy the desired elements from the real array, and pass the temporary array to the function.

I shouldn't have to do this though...

I think the best that you can do is.

float sAve(float stu[3][4]);
sAve(stu[x]); where x is a number of your choice (0 or 1).

I'm honestly confused, I thought I could just call 2 parts of the array to the function

I'd be tempted to make a subroutine like this:

Code:

void get_y_z_slice(  int const_x_val,                      /* The value of x for the yz plain*/
                     char (*input)[MAX_X][MAX_Y][MAX_Z],   /* The input 3D array */
                     char (*output)[MAX_Y][MAX_Z]);        /* Where the resulting plain is stored */

Yes I could use two arrays, but that's not the point of doing this

Originally Posted by Sorinx

I'm honestly confused, I thought I could just call 2 parts of the array to the function

You can like my second string printing example - But if you wanted a dimension (say, z) constant and to vary the other two and store it in another

Code:

 arr1[x][y] = arr2[x][y][2]

You are going to have to do it manually.

Everything in my notes says this should work the way it is without having to use 2 arrays

Originally Posted by Sornix

So if I do say int array[][4][5];
and I want to just take 4 and 5 I would make a prototype

Originally Posted by Sornix

Yes I could use two arrays, but that's not the point of doing this

What is the point of doing this? What are you trying to achieve?

Originally Posted by Sornix

See I tried using pointers but it gives me an error when compiling

I showed you how to send pointers to arrays into a function/subroutine correctly.
I'm sorry, but I just can't gauge what you are after...

I thought I made that clear my mistake. The point is to use 1 multi dimensional array, then to call that array to functions to compute different averages

so I want averages of stu[2][3][4] stu[3][4] and stu[4]

scanf's with %d need to be float (%f)


main didn't return 0 at the end


Variables m and l and unused


You can NOT pass a multidimensional array to a function/subroutine -> You must use a pointer.


I got your code working changing these things.

And by pointer to the arrays, I mean this:

Code:

float ave(float (*stu)[][3][4]);
float sAve(float (*stu)[][4]);

I get the same exact error...