How to get input from user with c/c++ (for operating system)

I am writing an operating system with C++ to learn (INCLUDING C) I learned a few functions such as printing to the screen, but I could not learn to receive input from the user and print to the screen. I looked at many sources, but I could not find what I wanted.What I want is to receive input from the user and print it on the screen and wait for a certain key to be pressed for an action. How can I do it?I will be glad if you can provide sample code.

loader.s

.set MAGIC, 0x1badb002.set FLAGS, (1<<0 | 1<<1).set CHECKSUM, -(MAGIC + FLAGS).section .multiboot    .long MAGIC    .long FLAGS    .long CHECKSUM.section .text.extern kernelMain.extern callConstructors.global loaderloader:    mov $kernel_stack, %esp    call callConstructors    push %eax    push %ebx    call kernelMain_stop:    cli    hlt    jmp _stop.section .bss .space 2*1024*1024;kernel_stack:

kernel.cpp

#include "includes/types.h"#include "includes/functions.h"#include "includes/colors.h"#include "includes/keyboard.h"using namespace std;typedef void (*constructor)();extern "C" constructor* start_ctors;extern "C" constructor* end_ctors;extern "C" void callConstructors(){    for(constructor* i=start_ctors;i!=end_ctors;i++){        (*i)();    }}extern "C" void kernelMain(void* multiboot_structure, uint32_t magicnumber){     print(COLOR_RED, "Hello!");    while(1);}

functions.h

#include "keyboard.h"#include "colors.h"static unsigned short* VideoMemory=(unsigned short*)0xb8000;int pos_print = 0;void print_title( unsigned char colour, const char *string) {    volatile unsigned char *vid = (unsigned char*) VideoMemory;    while(*string != 0)    {        *(vid) = *string;        *(vid+1) = colour;++string;        vid+=2;    }}void setChar(char character, short col, short row, unsigned char attr) {    volatile unsigned char* vid_mem = (unsigned char *) VideoMemory;    int offset = (row*80 + col)*2;    vid_mem += offset;    if(!attr) {        attr = 0x0f;    }    *(unsigned short int *)vid_mem = (attr<<8)+character;}void print_line( unsigned char colour, const char *string, int pos ) {    volatile unsigned char *vid = (unsigned char*) VideoMemory;    vid+=pos*160;    while(*string != 0)    {        *vid = *string;        *(vid+1) = colour;++string;        vid+=2;    }}void print( unsigned char colour, char string ) {    volatile unsigned char *vid = (unsigned char*) VideoMemory;    pos_print+=1;    vid+=pos_print*160;    while(string != 0)    {        *vid = string;        *(vid+1) = colour;++string;        vid+=2;    }}