#include <stdio.h>
#include <conio.h>
int main(void)
{
int i;
char far*video;
video=(char far*)0xB8000000L;
for(i=0;i<=3999; i=i+2)
{
*(video+i)='A';
*(video+i+1)=65;
}

Sorry late reply, as I m also new user of c programming don't know such knowlegde about vdu and graphic coding in c but it will help you!