OVERVIEW OF "C" PROGRAMMING (PART-II)

IDENTIFIERS

Identifiers are names of variables, functions, and arrays. They are user-defined names, consisting sequence of letters and digits, with the letter as the first character.

CONSTANTS

Values do not change during the execution of the program Types:

1.  Numerical constants:

a)  Integer constants

These are the sequence of numbers from  0  to  9 without decimal points or fractional part or any other symbols. It requires a minimum of two bytes and a maximum of four bytes.

E.g.: 10, 20, + 30, – 14

b) Real constants

It is also known as floating point constants.

Eg: 2.5, 5.342

2.  Character constants:

a)      Single character constants

A character constant is a single character. Characters are also represented with a single digit or a single special symbol or white space enclosed within a pair of single quote marks

Eg: ‘a’, ‘8’, “ ”.

b)      String  constants

String constants are the sequence of characters enclosed within double quote marks.

Eg: “Hello”, “india”, “444”

VARIABLES

It is a data name used for storing a data value. Its value may be changed during the program execution. The value of variables keeps on changing during the execution of a program.

DATA TYPES

OPERATORS

It indicates an operation to be performed on data that yields value.

Types

INPUT AND OUTPUT

Reading  data  from  input  devices  and  displaying  the  results  on  the  screen  are  the  two  main tasks of any program.

Formatted Functions

— The formatted input/output functions read and write all types of values

Input                                        Output

Scanf()                                    printf()

Unformatted Functions

— The unformatted input/output functions only work with the character data type.

Input                                        Output

getch()                                    putch()

getche()                                   putchar()

getchar()                                 put()

gets()

DECISION STATEMENTS

It checks the given condition and then executes its sub-block. The decision statement decides the statement to be executed after the success or failure of a given condition.

Types:

a)    If statement

b)    If-else statement

c)    Nested if-else statement

d)    Break statement

e)    Continue statement

f)     Go to statement

g)    Switch()  statement

h)    Nested switch () case

i)      Switch() case and Nested if

LOOP CONTROL STATEMENTS

Loop is a block of statements which are repeatedly executed for certain number of times.

Types

a)    For loop

b)    Nested for loops

c)    While  loop

d)    do while loop

e)    do-while statement with while loop

ARRAYS

It is a collection of similar data types in which each element is located in separate memory locations.

Types

a)    One dimensional array

b)    Two-dimensional arrays

c)    Three or multi-dimensional arrays

Operations

a)    Insertion

b)    Deletion

c)    Searching

d)    Sorting

e)    Merging

STRINGS

Character arrays are called strings.  Group of characters, digits, symbols enclosed within quotation marks are called as strings.

String Standard Function

FUNCTIONS

It is a self-contained block or a subprogram of one or more statements that performs a special task.

Declaration of functions

Function_name  (argument/parameter)

Argument declaration;

{

Local variable declaration;

Statement1;

Statement  2;

Return (value);

}

Call by value

In this type, value of actual arguments is passed to the formal arguments and the operation is done on the formal arguments. Any change made in the formal argument does not affect the actual arguments because formal arguments are photo copies of actual arguments.

Call by reference

In this type, instead  of  passing  values,  addresses  are  passed.  Function operates  on  address rather than values. Here the formal arguments are pointers to the actual argument