Array definition

Arrays are used in C to represent structures of consecutive elements of the same type. The definition of a (fixed-size) array has the following syntax:

Call by value

Call by value (also referred to as pass by value) is the most common evaluation strategy, used in languages as different as C and Scheme. In call by value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (frequently by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only its local copy is assigned—that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In computer programming, a parameter is a special kind of variable, used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are called arguments. An ordered list of parameters is usually included in the definition of a subroutine, so that, each time the subroutine is called, its arguments for that call can be assigned to the corresponding parameters.

In the C programming language, an external variable is a variable defined outside any function block. On the other hand, a local (automatic) variable is a variable defined inside a function block.

In computer programming, a global variable is a variable with global scope, meaning that it is visible (hence accessible) throughout the program, unless shadowed.

In computer programming, a static variable is a variable that has been allocated "statically", meaning that its lifetime(or "extent") is the entire run of the program. This is in contrast to shorter-lived automatic variables, whose storage is stack allocated and deallocated on the call stack; and in contrast to objects, whose storage is dynamically allocatedand deallocated in heap memory.

In computer science, a local variable is a variable that is given local scope. Local variable references in the functionor block in which it is declared override the same variable name in the larger scope. In programming languages with only two levels of visibility, local variables are contrasted with global variables. 

Function (mathematics)

A function f is commonly declared by stating its domain X and codomain Y using the expression

$$f: X \rightarrow Y$$

A_Little_C_Primer_Print_version

C-like languages

Implicit type conversion

Implicit type conversion, also known as coercion, is an automatic type conversion by the compiler. Some programming languages allow compilers to provide coercion; others require it.

In a mixed-type expression, data of one or more subtypes can be converted to a supertype as needed at runtime so that the program will run correctly. For example, the following is legal C language code: