Can someone pleae tell me how to write a medium size code systematically?? for example, I have one .c file for LCD, another .c file for keyboard, another .c file for ADC reading. main() is written as main.c. Now i have added all these source codes; but my doubt is how can I call these deifferent files from main; how compiler wil come to know that these many files make the code complete?? Is there any reading material available anywhere?? please help..