This document discusses various fundamental concepts in C programming such as flowcharts, pseudocode, control structures, variables, data types, operators, functions, arrays, structures, and input/output functions. It provides definitions and examples for each concept. Control structures covered include conditional statements like if-else and switch-case, as well as loops like while, do-while and for. Data types discussed are integer, floating point, character and string constants. Key concepts like variables, arrays, structures, functions and their declarations are also summarized.

1.  FLOW CHARTS
 PSEUDO CODE

2.  They are very precise. They represent our
thoughts exactly.

3. FUNDAMENTAL CONDITIONAL AND
CONTROL STRUCTURES:
Branching:
Two way branching:
Eg: if A > B, then Print A, otherwise
Print B
Multiway branching:
Eg: if n is 0, then Print ‘ zero’
1, then Print ‘ one’
2, then Print ‘ two’
3, then Print ‘ three’

4. ITERATION:
The third fundamental technique is
Iteration. It means repeating a set of
actions again and again.

5.  Pseudo code can be used to represent a
procedure for doing something.
 These are in between the English and the high
level computer languages.
The flow chart fundamental control structures
for branching and iteration correspond to the
following pseudo code.
 if…then…else
 if…then
 For…to…do…
 While…do…

8. Consider the statement:
number = number + 1;
The tokens are,
number - identifer
(variable)
= - operator
+ - operator
1 - constant
; - punctuation

9. A constant is of numeric or non-numeric type.
It can be a number, a character or a character
string that can be used as a value in a
program.
 Numeric constants are of three types:
• integer constant
• floating-point constant
• character constant
 A non-numeric data can be called as a literal.
String Literal:
A string literal or a string constant is
a sequence of characters from the system’s
character set, enclosed in double quotes.

10.  Integer Constant:
An integer constant is a decimal number
(base 10) that represents an integral value (the
whole number). It comprises of the
digits 0 to 9.
 Floating - point Constant
A floating-point constant is a signed real
number. It includes integer portion, a decimal
point, fractional portion and an exponent. Eg.
5.864E1
 Character Constant
A character is a letter, numeral or special symbol,
which can be handled by the computer system.
These available symbols define the system’s
character set.
Eg. ‘1’, ‘a’, ‘+’, and ‘-‘ are the valid character
constants.

11.  Identifiers are the names that are to be given to the variables, functions,
data types and labels in a program.
 The name of a variable can consist of alphabets (letters) and numbers.
 Other characters are not allowed in the name of a variable except an
underscore character.
 The variable name starts with an alphabet and its length may vary from one
character to 32 characters.
 The first character in a variable’s name should be an alphabet,
 Keywords (which have special meaning in C) cannot be used as identifiers
The valid variable names are:
 x
 length
 x_value
 y_value
 A123

12. POINTER VARIABLES
The variables in C are classified into ordinary
variables and pointer variables.
int x;
x = 10;
int *y;
A pointer variable assumes only address as its value. Each
variable takes some locations in the main memory according
to its type. Every location in the main memory is addressable.
y=&x;
• y represents the address of the variable x (&x)
• *y represents the value of the variable x (x)

13. UNARY
BINARY
TERNARY

14. Variable = Expression;
i++ postfix form
++i prefix form
c = a+b; arithmetic expression
c = a > b; relational expression
f = d = e; assignment expression
x = i++; /*postfix increment
expression on the right side*/
printf()
scanf()

15.  [ ] - represent array index
 { } - cover the body of the function
 ( ) - represent a function, to group items
 < > - enclose a header file in a preprocessor statement
 “ “ - represent string literals
 ‘ ‘ - represent a character constant
 /* */ - represent a comment
 ; - a statement terminator
 , - to separate items
KEYWORDS
They cannot be used as identifiers for the variables in a program.
auto break case char continue default
do else if float for int return static
switch while
A keyword must be specified precisely as given in the list.

17.  Each and every line of a C program can be
considered as a statement. There are
generally four types of statements. They are:
 • Preprocessor statement
 • Function header statement
 • Declaration statement
 • Executable statement
#include <stdio.h> => Preprocessor Statement
main() => Function header Statement
{
int a,b,c; => Variable declaration statement
int add(int,int); => Function declaration statement
a = 10; => Executable statement
}

18. PRINTF() STATEMENT:
PRINTF( FORMATTING STRING, CONTROL STRING)
printf(“%d”, n);
Formatting character Data type
%d int
%f float
%c char
%s char [ ]
%ld long int
%lf long float or double
control string of printf() function are:
‘n’ - new line character
‘t’ - tab character
‘b’ - backspace character
Eg: printf(“the value of i = %d n”, i);

19.  To read a value from the keyboard (standard
input), the function scanf() is used.
 The prototype of scanf() is similar to the
prototype of printf().
int x;
scanf(“%d”, &x);
• The second parameter of the above scanf()
function is &x, which represents the
address of x.
• & is the address of operator and when it is
being used with a variable, it provides the
address of that variable.

20.  The user or programmer can write functions to
define specific tasks that may be used at many
points in a program.
 The function which calls another function is
termed as calling function and the other is
termed as called function.
 A function declaration may be called
as a function prototype or a function model. The
function prototype has four components.
• Name of the function
• Return value type
• Number of parameters
• Type of each parameter

21. Function
protype
Function
definition

22. Storage
classes
auto
extern
register
static

23. if
• if(relational
expression)
• statement1
if..else
• if(relational
expression)
• statement1;
• else
• statement2;
switchcase
• switch(cond.expr.)
• {
• case1 expr1:
• ....
• break;
• case2 expr2:
• ....
• break;
• default:
• }

24. while do...while for
•
Initialization
while(condition)
{
……..;
processing stmts
…….;
increment
}
for(initialization;
condition;
increment)
{
body of the loop;
}
do
{
…….;
}
while(condition);

25.  DEFINITION:
An array is a collection of homogeneous elements
i.e. elements of similar data type.
 EXAMPLE:
int a[100];
 DECLARATION STMT:
int a[10]; /* => array declaration statement */
a[0]=6; a[1]= 7; …..a[99]=67;

26. A multidimensional
array has been
considered as an
array of
arrays in C language
DECLARATION
int a[3][3];
a[0] =[ 1 2 3 ]
a[1] =[ 4 5 6 ]
a[2] =[ 7 8 9 ]

27.  Structures are derived data types in C
language.
 Structures are used to create user-defined
types. Structures are commonly used to
define records to be stored in files.
 A file is a collection of records.
 A record is a collection of fields of
information.

28.  Roll number: an integer field
 Name: an array of characters
 age: an integer field
 Consider the following structure definition:
Eg:
struct student
{
int rollno;
char name[24];
init age;
} x, y;

29. Accessing the members of the
Structures:
x.rollno = 1000;
y.rollno = 1001;
Pointers to Structures:
struct student *ptr;
struct student s1;
ptr = &s1;
An Array of Structures:
struct student x[5];
x[0].rollno, x[0].name, uctures