task_matrix

function matrix = task_matrix(matrix)
    [N,M] = size(matrix);
    c = 1;
    for i = 1:M
        sum = 0;
        for j = 1:N
            sum = sum + matrix(j,i);
        end
        if ( sum / N < 0 )
            for k = i:(-1):c+1
                for j = 1:N
                    matrix(j,k) = matrix(j,k-1);
                end
            end;
            for j = 1:N
                matrix(j,c) = 0;
            end
            c = c + 1;
        end
    end
end