Using matrix as 1D array parameter

Question

I have a 2D array that I need to process one column at a time. I wrote a sample code to illustrate what I want to do. It will obviously not compile.

float a[3][16]; // Create 2D array

void function1() // This function will be called from my application
{
    for (int i=0; i<16; i++) // For each column of the 2D array "a"
    {
        // Call this function that only take 1D array parameters
        function2(a[][i]); // What I want is all rows in column i
                           // MATLAB syntax is: function2(a(:,i));
    }
}

void function2(float b[])
{
    // Something
}

I know I can make a temporary array, save each columns into that and use it as parameter in function2. I would like to know if there is a better method or how you would do this?

Answer 1

The best way would be to pass the entire 2d array to function2() along with a parameter that selects the column. Then just iterate along the axis.

for (int i=0; i<16; i++) // For each column of the 2D array "a"
{
    function2( a , i ); 
}

---

void function2(float b[Y][X] , size_t col )
{
    for( size_t i = 0 ; i < Y ; i++ )
        b[i][col] = ... 
}