Matrix Keypad + OLED Question with U8g Library

Projects Programming
1

How to display two digits on an OLED from two presses on a keypad? I believe it works differently than an LCD. I'm using the u8g library. See video: Arduino - YouTube

2

why isn't is obvious that you need to post the code that you are using?

void dispOled(
    const char  *s0,
    const char  *s1,
    const char  *s2,
    const char  *s3,
    bool         clr )
{
    if (clr)
        display.clear();

    display.setTextAlignment(TEXT_ALIGN_LEFT);

    if (s0)  {
        display.drawString(0, DISP_Y0,  s0);
    }
    if (s1)  {
        display.drawString(0, DISP_Y1, s1);
    }
    if (s2)  {
        display.drawString(0, DISP_Y2, s2);
    }
    if (s3)  {
        display.drawString(0, DISP_Y3, s3);
    }
    display.display();
}

// display menu
static MenuStim_t
dispMenu (void)
{
    timeSec  =  msec / 1000;

    if (! loco)  {
        sprintf (s, "%2d:%02d   No Loco", timeSec / 60, timeSec % 60);
    }
    else  {
        sprintf (s, "%2d:%02d  Loco %d", timeSec / 60, timeSec % 60, loco);
    }

    dispOled (s, 0, 0, 0, CLR);
    return updtMenu ();
}

#include "SSD1306Wire.h"
    // init OLED display
    display.init();
    display.flipScreenVertically();
    display.setFont(ArialMT_Plain_16);
    display.clear();
    display.setTextAlignment(TEXT_ALIGN_LEFT);
    display.setColor(WHITE);