Which compiler you are using???
If you are using MikroC Pro… there is a built in function IntToStr() use it..
If you are using other compiler… extract digit by digit… and display it…
for eg: 45 can be displayed by following method..
i = 45;
DisplayCharacter((i%10)+48);
i = i/10;
DisplayCharacter((i%10)+48);
Hope you got the logic..