Reading source code to learn programming

The habit of reading source code helps programmers to:

• Learn problem solving techniques
• Recognize good software development practices
• Recognize the negative consequences of bad software development practices
• Learn programming techniques

In professional environments, reading source code is often required to:

• Improve existing software
• Fix errors in existing software
• Re-use techniques and existing software
• Inspect software during the testing phase

C is a procedural language

The main() function is required for all C programs.

• The main() function is the where the program starts.
• The program ends when the main() function ends.
• The main() function should be defined before all other functions.

Preprocessor directives

The preprocessor directive is used to include the source code from the stdio.h header file into the current program.

• Header files have names ending with a .h extension.
• Header files used with a program should be included at the top of the source code file for easier maintenance.

Statements

C programs use 2 types of statements.

• Simple statements end with a semicolons.
• Compound or complex statements are enclosed in curly braces. They contain one or more simple statements.

Function calls and input parameters

Function calls require a pair of parentheses after the name of the function.

• Optionally, input parameters are provided by including it within the parentheses.
• A comma is required to separate multiple input parameters.

Source code comments

Comments start with /* and continue until it reaches a matching */ end.

Do not use C++, Java or PHP style comments, which use a double forward slash at the start of comments.

Steps to create C programs

Reserved keywords in the C language

Reserved keywords may not be used as names of functions or data variables.

auto	double	int	struct
break	else	long	switch
case	enum	register	typedef
char	extern	return	union
const	float	short	unsigned
continue	for	signed	void
default	goto	sizeof	volatile
do	if	static	while