differs in levels of in direction from / different types for formal and actual

Hi there, the purpose of this program is to find whether numbers along the diagonal of matrix are same or not.

Code:

#include <stdio.h>
int checkdiag(int matrix[][100], int size)
{
	int i,j,status;
	for(i=0; i <size; i++)
	{
		for(j=0; j <size; j++)
		{
			status = 0;
			if(matrix[i][j]==matrix[i+1][j+1])
			{
				status =1;
			}
		}
	}

	return status;
}

int main(void)
{
	FILE *ifp;
	int **matrix;
	int size,i,j,status;
	ifp = fopen("matrix.txt","r");
	fscanf(ifp,"%d",&size);
	matrix = (int**)calloc(size,sizeof(int));
	for(i=0; i < size; i++)
	{
		matrix[i]= (int*)calloc(size,sizeof(int));
	}
	while(!feof(ifp))
	{
		for(i=0; i< size; i++)
		{
			for(j=0; j < size; j++)
			{
				fscanf(ifp,"%d",&matrix[i][j]);
			}
		}
	}
	status = checkdiag(matrix,size);
	if(status==1)
	{
		printf("The Matrix Is %d x %d and and all the numbers on the main diagonal are the same.");
	}
	else
	{
		printf("Numbers along diagonal are not the same");
	}
	fclose(ifp);
	free(matrix);
	return 0;
}

in file matrix1.txt is this:

3
4 5 6
7 8 9
3 6 7







and the error im getting follows:

lab10.c(42) : warning C4047: 'function' : 'int (*)[100]' differs in levels of in
direction from 'int **'
lab10.c(42) : warning C4024: 'checkdiag' : different types for formal and actual
parameter 1

Please Help me out: Thank You.

Well, it seems like a pretty clear message: a two-dimensional array of integers ("int (*)[100]") is not the same thing as a pointer to a pointer to int ("int **"). If you intend to pass such a thing to your function, your function should expect such a thing.

Then, whats the best way to dynamically allocate a 2D array and pass that array into a function?

I suggest using a little abstraction:

Code:

typedef struct
{
    int **data;
    size_t size;
} SquareMatrix;

Now, you write functions that work with SquareMatrix objects (or rather, pointers to SquareMatrix objects). The function can easily access both the data in the matrix, as well as the size (or perhaps more accurately, order) of the matrix.

Also, instead of having data as a pointer to a pointer, you could make it just a pointer to an int, and then compute offsets.

sorry but the requirement my prof said was to use

int checkdiag(int matrix[][100], int size)

for user defined function... thatswhere im having problem with :|

If i were to use structure wouldnt it be

int checkdiag(SquareMatrix variable) ?

> int checkdiag(int matrix[][100], int size)
If you've got this, then you need to have either

int array[100][100];

or
int (*array)[100] = malloc( 100 * sizeof *array );