TechOnespot

    Function C program has at least one main() function. The use of function in a program makes it modular. Modularity means partitioning a complex problem into small sub-problems which are easy to understand and maintain. There are two categories of functions in C. (1) Library functions or System defined functions (2) User defined functions Library Functions  :-The C language standard library provides many built-in functions that our program can use. They are also known as system defined functions. For example printf( ), scanf(), sqrt() and cos are examples of library functions User Defined Functions The functions developed by user are known as user defined functions. The main() is special type of user defined function in C. The program execution starts from main() function. Testing and debugging of such program may be become difficult for programmer. Variables By scope of variable we mean the part of program where the variable is accessible. In C scope of variables are of two types: