i have problem with acessing 2d array via function - c

Question

i am learning pointers and i write these code to add two martix via function, it compile well and give correct answer for 2x2 matrix but for more than two row and col it fails when i try it with 3x3 matrix [0][0] element for the first matrix it automaticaly become 6 and [1][0] it became 9 every time, i can't figure out why this happen
#include <stdio.h>
//-----------------Function------------------
void add(int (*p1)[10], int (*p2)[10], int (*p3)[10], int r, int c);
void get(int (*p1)[10], int r, int c);
void print(int (*p1)[10], int r, int c);
//---------------Main Program----------------
int main()
{
//declartion
int i, j, r, c;
printf("\n\tenter the row and column of matrix\n\t");
scanf("%d %d", &r, &c);
int m1[r][c], m2[r][c], m3[r][c];
printf("\n\tenter the element of first matrix\n\t");
get(m1, r, c);
print(m1, r, c);
printf("\n\tenter the element of second matrix\n\t");
get(m2, r, c);
print(m2, r, c);
add(m1, m2, m3, r, c);
printf("\n");
print(m3, r, c);
return(0);
}
//-------------Define Function---------------
//get()
void get(int (*p1)[10], int r, int c)
{
int i, j;
for(i = 0; i < r; i++)
{
printf("\n\t");
for(j = 0; j < c; j++)
{
scanf("%d", (*(p1+i)+j));
}
}
}
//--------------------X----------------------
//add()
void add(int (*p1)[10], int (*p2)[10], int (*p3)[10], int r, int c)
{
int i, j;
for(i = 0; i < r; i++)
{
for(j = 0; j < c; j++)
{
//printf("\n%d %d = %d & %d", i, j, *(*(p1+i)+j), *(*(p2+i)+j));
*(*(p3+i)+j) = *(*(p1+i)+j) + *(*(p2+i)+j);
}
}
}
//--------------------X----------------------
//print()
void print(int (*p1)[10], int r, int c)
{
int i, j;
for(i = 0; i < r; i++)
{
printf("\n");
for (j = 0; j < c; j++)
{
printf("\t%d", *(*(p1+i)+j));
}
}
}
//--------------------X----------------------

Answer 1

Drop the array pointer notation and the fixed size. Use variable-length arrays based on the parameters.
Remove useless comments like // get ... void get...
Don't use unreadable de-referncing with *(arr+i) when you could be writing readable arr[i].
Print new line after each row, not before each row.
Here's a cleaned up program which compiles. I haven't tested it.
#include <stdio.h>
void add (int r, int c, int p1[r][c], int p2[r][c], int p3[r][c]);
void get (int r, int c, int p1[r][c]);
void print (int r, int c, int p1[r][c]);
int main (void)
{
int i, j, r, c;
printf("\n\tenter the row and column of matrix\n\t");
scanf("%d %d", &r, &c);
int m1[r][c], m2[r][c], m3[r][c];
printf("\n\tenter the element of first matrix\n\t");
get(r, c, m1);
print(r, c, m1);
printf("\n\tenter the element of second matrix\n\t");
get(r, c, m2);
print(r, c, m2);
add(r, c, m1, m2, m3);
printf("\n");
print(r, c, m3);
return(0);
}
void get (int r, int c, int p1[r][c])
{
for(int i = 0; i < r; i++)
{
for(int j = 0; j < c; j++)
{
scanf("%d", &p1[i][j]);
}
}
}
void add (int r, int c, int p1[r][c], int p2[r][c], int p3[r][c])
{
for(int i = 0; i < r; i++)
{
for(int j = 0; j < c; j++)
{
p3[i][j] = p1[i][j] + p2[i][j];
}
}
}
void print (int r, int c, int p1[r][c])
{
for(int i = 0; i < r; i++)
{
for (int j = 0; j < c; j++)
{
printf("\t%d", p1[i][j]);
}
printf("\n");
}
}