passing uninitialized 2d array to function

[sangamesh]

Hi,

The below program does some operations on multiple matrices. For reading these multiple matrices, am using a function readmat().

#include<stdio.h>
void readmat(int *a)
{
    int i,j;
    for(i=0;i<2;i++)
    for(j=0;j<2;j++)
        scanf("%d",a[i][j]);
}

void printmat(int *a)
{
    int i,j;
    for(i=0;i<2;i++)
    {
        for(j=0;j<2;j++)
        printf("\t%d",*a[i][j]);
        printf("\n");
    }
}

int main()
{

    int a[2][2], b[2][2], c[2][2];
    printf("\n Enter Matrix A:\n");
    readmat(&a);
    printf("\n Enter Matrix B:\n");
    readmat(&b]);
    printf("\n\n Matrix A: \n");
    printmat(&a);
    printf("\n\m Matrix B: \n");
    printmat(&b);
    return 0;
}

This program compiles well. But fails during runtime after reading 1st element of the array. I guess, the problem is here with passing the uninitialized 2d array to function by reference. Can someone show me how to do this?
-
Thanks

[Bayint Naung]

int readmat(int a [][2]) ;
or
int readmat( int (*a)[2]);

c-faq

[cas]

This program compiles well.

I really can't believe this. a[i][j] should be absolutely meaningless when you have int *a. At the very least, your compiler should issue a diagnostic for it; and I would expect an error rather than a warning, because I don't see how a compiler could even try to interpret it.

The call readmat(&b]) certainly should bring about an error from your compiler. You really should copy and paste code, and not just re-type it. You've got a good chance of introducing errors if you re-type it.

Beyond that, all other calls to readmat() and printmat() require diagnostics for invalid pointer conversions.

In short, any compiler that builds this code with no diagnostics is no good and should be scrapped immediately.

[sangamesh]

The call readmat(&b]) certainly should bring about an error from your compiler. You really should copy and paste code, and not just re-type it. You've got a good chance of introducing errors if you re-type it.

Am sorry, While copying, I think I didn't copy the code which was compiling. Without the modification, i.e. "]" it was compiling well. I'm using codeblocks with GCC on Fedora 11.

I followed the steps provided by Naung and got the program working

Thanks