Mess, to be sorted

//#include <iostream>
//#include <ctime>
//using namespace std;
#include <stdio.h>
#include <time.h>
//from here: https://otvet.mail.ru/question/213471066

int main()
{
    //setlocale(LC_ALL, "ru");
    srand(time(NULL));

    const int ROWS = 4, COLS = 4;
    int step, max, sum ;//*** there was l instead of step, different meaning
    int matrix[ROWS][COLS];

    //populates & prints array
    for (int i = 0; i < ROWS; i++)
    {
        for (int k = 0; k < COLS; k++)
        {
            matrix[i][k]=i*ROWS+k+1;
            printf(" %d ",matrix[i][k]);
        }
        printf("\n");
    }
    printf("\n\n\n");

    //ONE
    max = step = sum= 0;//the smalles available number
    for (int i = 0; i < ROWS; i++)
    {
        for (int k = 0; k <COLS-step ; k++)//*** was(int k = 1; k <= l; k++)
        {
            if (max < matrix[i][k])
                max = matrix[i][k];
            printf("%d ",matrix[i][k]);//*** was[k-1]
            sum += matrix[i][k];//*** was [k-1]
        }
        step++;
        printf("\n");
    }
    printf("\n\n\nONE: Biggest element: %d Sum: %d\n\n\n",max,sum);

    //TWO
    max = step =sum= 0;
    for (int i = 0; i < ROWS; i++)
    {
        for (int a = 0; a < step*2; a++)//int a = 2; a < l*2; a++
            printf(" ");//cout << " ";
        for (int k = step; k < COLS; k++)
        {
            if (max < matrix[i][k])//***k-1
                max = matrix[i][k];//*** k-1
            printf("%d ",matrix[i][k]);//*** k-1
            sum += matrix[i][k];//*** k-1
        }
        step++;
        printf("\n");
    }
    printf("\n\n\nTWO:Biggest element: %d Sum: %d\n\n\n",max,sum);

    //THREE
    max = sum = step = 0;
    for (int i = 0; i < ROWS; i++)
    {
        for (int a =0 ; a < step*2+4; a++)
            printf("0");
        for (int k = step; k <= COLS - step; k++)
        {
            if (max < matrix[i][k])
                max = matrix[i][k];
            printf("%d ",matrix[i][k]);
            sum += matrix[i][k];
        }
        step--;
        printf("\n");
    }
    printf("\n\n\n\nTHREEBiggest element: %d Sum: %d\n\n\n",max,sum);

    //FOUR
    sum = max = step = 0;
    for (int i = 0; i < ROWS; i++)
    {
        for (int k = 0; k < step; k++)
        {
            if (max < matrix[i][k])
                max = matrix[i][k];
            sum += matrix[i][k];
            printf("%d\t",matrix[i][k]);
        }
        step++;
        printf(" ");
    }
    printf("\n\n\n\Biggest element: %d Sum: %d\n\n\n",max,sum);

    return 0;
}