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’
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…
6.
7.
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)
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.
16.
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
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