How to create a Header File in C Language or In C How to make User Defined Header Files :- First we have to install or copy Turbo C++ in our computer. If we copy the TC folder, which should be copied into the same Drive as the Source Computer Drive, otherwise an Error will occur see more . Any way let us guess the C Program in "C:\TC\BIN\TC.EXE" then usually the Header files residing in "C:\TC\INCLUDE\" directory. our working directory is "C:\TC\BIN\" Let us try How to create a "Hello World!" Program with clrscr() SDF :- #include<stdio.h> #include<conio.h> void main() { clrscr(); printf("Hello World!"); } in the above program, we used clrscr() as a System Defined Function , because it is defined in conio.h and it is included. Let us try How to create a "Hello World!" Program with clrscr() as UDF and User Defined Header File :- Step 1: fist let us make a header file named "my_header_file.h" and i...