Introduction to C language
Type combination and promotion
Floating point types
Int vs float arithmatic
Unary Increment Operators
Pre and Post Variations
C Programming Cleverness and Ego Issues
Other Assignment Operators
As in most languages, a variable declaration reserves and names an area in memory at run
time to hold a value of particular type. Syntactically, C puts the type first followed by the
name of the variable. The following declares an int variable named "num" and the 2nd line stores the value 42 into num.
num = 42;
A variable corresponds to an area of memory which can store a value of the given type. Making a drawing is an excellent way to think about the variables in a program. Draw each variable as box with the current value inside the box. This may seem like a
"beginner" technique, but when I'm buried in some horribly complex programming problem, I invariably resort to making a drawing to help think the problem through.
Variables, such as num, do not have their memory cleared or set in any way when they are allocated at run time. Variables start with random values, and it is up to the program
to set them to something sensible before depending on their values.
Names in C are case sensitive so "x" and "X" refer to different variables. Names can
contain digits and underscores (_), but may not begin with a digit. Multiple variables can
be declared after the type by separating them with commas. C is a classical "compile
time" language -- the names of the variables, their types, and their implementations are all
flushed out by the compiler at compile time (as opposed to figuring such details out at run
time like an interpreter).
float x, y, z, X;
Want more information and Video ???