Make Your Own Header File ? Step1 : Type this Code int Multiplication( int a, int b) { return (a*b); } In this Code write only function definition as you write in General C Program Step 2 : Save Code Save Above Code with [.h ] Extension . Let name of our header file be myhead [Multhead.h ] Compile Code if required. Step 3 : Write Main Program #include<stdio.h> #include "Multhead.h" void main() { int number1=10,number2=10,number3; number3 = Multiplication(number1,number2); printf( "Addition of Two numbers : %d" ,number3); } Include Our New Header File . Instead of writing < Multhead.h> use this terminology “Multhead.h” All the Functions defined in the Multhead.h header file are now ready for use . Directly call function Multiplication(); [ Provide proper parameter and take care of return type ] Note While running your program precaution to be taken : Both files [ Multhead.h and sample.c ] should be in same folder. Technorati Tag...