Changing the sign of array values in C - c

Question

I need to write a function that takes the elements in an array and changes the sign (ex. 3 --> -3 or -3 --> 3). l want use this array (int a[2][3] = { { 55,-44,},{1, -4},{6,11} };) instead of ( int a[] = { 5,6,-4};)
What should I do?
#include <stdio.h>
void change_sign(int* beta)
{
for (int i = 0; i < 3; i++) {
beta[i] = -beta[i];
}
}
int main(void)
{
int a[] = { 5, 6, -4};
for (int i = 0; i < 3; i++) {
printf("%d ", a[i]);
}
printf("\n");
change_sign(a);
for (int i = 0; i < 3; i++) {
printf("%d ", a[i]);
}
return 0;
}

Answer 1

For starters it seems you mean this array
int a[3][2] = { { 55,-44,},{1, -4},{6,11} };
instead of this
int a[2][3] = { { 55,-44,},{1, -4},{6,11} };
In any case if your compiler supports variable length arrays then the function can look like
void change_sign( size_t m, size_t n, int a[][n] )
{
for ( size_t i = 0; i < m; i++ )
{
for ( size_t j = 0; j < n; j++ )
{
a[i][j] = -a[i][j];
}
}
}
and call the function like
change_sign( 3, 2, a );
Otherwise the function can look like
#define N 2
void change_sign( int a[][N], size_t m )
{
for ( size_t i = 0; i < m; i++ )
{
for ( size_t j = 0; j < N; j++ )
{
a[i][j] = -a[i][j];
}
}
}
and called like
change_sign( a, 3 );