Father of C -
Dennis Ritchie
First Computer Programmer - Ada
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First Computer Programmer - Ada
Cut - shift + del
Paste - shift + insert
Copy - ctrl + insert
Clear - ctrl + del
Compile - alt + F9
Run - ctrl + F9
To see the output - alt + F5
1.
Data Type in C
Data Type Meaning Size
(in bytes)
char(Range -128 to +127) a character 1
int(Range -32768 to +32767) an integer 2
float a single precision real
number 4
double a double precision real number 8
void valueless 0
(The void data type is not used as often as the above four.)
C Data Types
|
|--------------------------------------------|
Primary Data Types Secondary
Data Types
1. Character 1. Array
i. Unsigned Char
ii. Signed Char
2. Integer 2. Pointer
i. Short
ii. Long
3. Float 3.
Structure
4. Double 4. Union
5. Void 5. Enum etc.
Integers
-
Integers data type can be categorised into two parts;Long and short.
- Long
integers require twice the space in memory than ordinary integers do.
-
Therefore long integers occupy four bytes of memory.
- The
value of a long integer can vary form -2147483648 to +2147483647.
- Long
integers declared using the keywords long. For example:
long int i;
- Short
integers require less space in memory and thus speed up the program execution.
- Short
integer is nothing but our ordinary int.
- Short
integers are declared using keywords int. For example:
int i;
- If we
add the suffix 'L' or 'l' at the end of the number, then it would be becoming
as a long integer and hence occupy 4 bytes.
Constants and Variables
- A
constant is a quantity that does not change. This quantity can be stored at a
location in the memory of the computer.
- Real
constants are often called Floating Point constants.
- The
real constants could be written in two forms; Fractional (426.0,
+325.34,-32.76) and Exponential (+3.2e-5, 4.1e8,-3.2e-5) Form.
- Range
of real constant expressed in exponential form is -3.4e38 to 3.4e38.
- The
part appearing before 'e' is called mantissa, whereas the part following 'e' is
called exponential.
- In
place of a small case 'e' a capital 'E' can also be used.
Rules for Constructing
Variable Names
- A
variable name is any combination of 1 to 8 alphabets, digits or underscores.
- Some
compilers allow variables names whose length could be upto 40 characters. But
it is recommended to stick on 8 characters.
- The
first character in the variable name must be an alphabet.
- No
commas, blanks or special character (except underscore) are allowed within a
variable name.
Scope of Variables
-
Variables can have two types of scopes: Local and Global.
- A
variable with a global scope is accessible to all the statements in the
program, whereas the one with local scope is available only to certain selected
statements in the program.
- Global
variables are declared outside all functions whereas the local variables are
defined inside a function.
C Keywords
-
Keywords also known as 'Reserved Word'.
-
Keywords are the words whose meaning has already been explained to the C compiler.
- The
keywords cannot be used as variable names.
- There
are 32 keywords available in C, for example: break, case, else, char, if, for,
void etc.
C Programming
- A
comment can be enclosed within /* */
(for multiple line comment) or // (for single line comment).
Printf(): It is a
function which is used to print the value contained in a variable on the
screen.
Syntax: printf("<format
string">,<list of variable>);
<format string>
could be %c (for character), %d(for integer),%f(for float values).
Example:
printf("%d",n1);
/n: It is
called a newline and takes the cursor to the next line.
Example:
printf("Average=%d\nSum=%d",avg,sum);
Scanf(): It is
used for supplying the values in the variables.
Syntax: scanf("<format
string">,&<list of variable>);
Example:
scanf("%d",&n1);
Integers, Signed &
Unsigned
When we
know in advance that the stored value in a given integer variable will always
be positive, then we can declare the variable to be unsigned, as in;
unsigned int car_park;
With
such a declaration, the range of permissible integer values will shift from the
range -32768 to +32767 to the range 0 to 65535. Thus declaring the integers as
unsigned almost doubles the size of the largest possible value. Unsigned
integer occupies two bytes. The following unsigned declarations are same;
short unsigned int i;
unsigned int i;
unsigned i;
The way
there exists a short unsigned int, there also exists a long unsigned int which
has a range of 0 to 4294967295 and occupies four bytes of memory.
By default
a short int is a signed short int and a long int is a signed long int.
Char, Signed & Unsigned
Signed
and unsigned chars, both occupying one byte each, but having different range.
A signed
character is same as our ordinary char and has a range from -128 to +127;
whereas an unsigned char has a range from 0 to 255.
#include<stdio.h>
void
main
{
char ch=291;
printf(“%d%c\n”,ch,ch);
}
Output is
35 #
Since
variable ch has defined as char, therefore it cannot take a value bigger than
+128. But when value exceeds +127, an appropriate value from the other side of
the range is picked up and stored in ch. In this case, value is 35 and its
corresponding character is # get printed.
Program1:
#include<stdio.h>
void
main()
{
char c;
unsigned char d;
int i;
unsigned int j;
long int k;
unsigned long int m;
float x;
double y;
scanf(“%c%c”,&c,&d);
printf(“%c%c”,c,d);
scanf(“%d%u”,&i,&j);
printf(“%d%u”,i,j);
scanf(“%ld%lu”,&k,&m);
printf(“%ld%lu”,k,m);
scanf(“%f%lf”,&x,&y);
printf(“%f%lf”,x,y);
getch();
}
Tags
B.Tech