Finding Nonzero Minimum in an Array where index 0 is 0 C++

Question

I am working on a project for my computer science class, but it requires me to find the minimum in a 2d array row, then return the index of the column, then next search the row with that column index. I am currently trying to get it to correctly find all the mins. The function I have now finds the right min for all rows except the first row which starts with a zero. Here is the Function:

int ComputeLowestPheromone(int matrix[][SIZE], int visitedColns[], int currRow)
{
    int row_min[SIZE];
    for(int i = currRow; i < SIZE; ++i)
    {
        row_min[i] = matrix[i][0];
        for(int j = 0; j < SIZE; ++j)
        {
            if(matrix[i][j] == 0)
            {
                continue;
            }

            if(row_min[i] > matrix[i][j])
            {
                row_min[i] = matrix[i][j];
            }
        }
    }

    for(int i = 0; i < SIZE; ++i)
    {
        cout  << "Row Min " << i << ": " << row_min[i] << endl;
    }
}

The Current output: CurrentOutput

So my question is, why is it correctly ignoring zero for all rows except the first? And once I have that solved, a tip on how to save that current index correctly would be awesome.

Answer 1

Change your initialization from

row_min[i] = matrix[i][0];

to

row_min[i] = std::numeric_limits<int>::max();

Answer 2

This assignment of row_min is causing the issue:

row_min[i] = matrix[i][0];

You are initializing this to presumably a zero value.

if(row_min[i] > matrix[i][j])
{
    row_min[i] = matrix[i][j];
}

Although you are normally using continue to avoid 0 assignment you have already assigned the value to 0 and this if statement will not run. Initialize row_min to row_min[i] = 0xffffffff or std::numeric_limits<int>::max(); 0xffffffff is assuming 32bit int.