Arrays 2 Dimensional Unit 2 Part 1.pdf

Jagannath Institute of Management Sciences
Vasant Kunj-II, New Delhi - 110070
Subject Name: Programming In C
Department of Information Technology
Created By: Dr. Arpana Chaturvedi
@Dr. Arpana Chaturvedi

Subject: Programming In C
Topic: Unit II- Part I
Two Dimensional Arrays

Topics to be Covered
▰ Two dimensional arrays
▰ Addition/Multiplication of two matrices
▰ Multiplication of two matrices
▰ Transpose of a square matrix
▰ Strings-Null terminated strings as array of characters
▰ Standard library string functions

Two dimensional Arrays in C

Arrays of Array

User View and memory View

Data Types in C

Storage Classes

Storage Classes in C
Storage class specifiers in C language tells the compiler where to store a variable,
how to store the variable, what is the initial value of the variable and life time of the
variable.
SYNTAX:
▰ storage_specifier data_type variable _name;
TYPES OF STORAGE CLASS SPECIFIERS IN C:
▰ There are 4 storage class specifiers available in C language. They are,
▰ auto
▰ extern
▰ static
▰ register

Types of Storage Specifiers in C
Storage Specifier Description
auto
Storage place: CPU Memory
Initial/default value: Garbage value
Scope: local
Life: Within the function only.
extern
Storage place: CPU memory
Initial/default value: Zero
Scope: Global
Life: Till the end of the main program. Variable definition might be
anywhere in the C program.
static
Storage place: CPU memory
Initial/default value: Zero
Scope: local
Life: Retains the value of the variable between different function calls.
register
Storage place: Register memory
Initial/default value: Garbage value
Scope: local
Life: Within the function only.

Key Points to use Storage Specifiers in C
▰ For faster access of a variable, it is better to go for register specifiers rather than
auto specifiers.
▰ Because, register variables are stored in register memory whereas auto variables
are stored in main CPU memory.
▰ Only few variables can be stored in register memory. So, we can use variables as
register that are used very often in a C program.

EXAMPLE PROGRAM FOR AUTO
VARIABLE IN C:
The scope of this auto variable is within the function only. It is
equivalent to local variable. All local variables are auto variables
by default.

EXAMPLE PROGRAM FOR STATIC
VARIABLE IN C:
▰ Static variables retain the value of the variable between
different function calls.

EXAMPLE PROGRAM FOR EXTERN
VARIABLE IN C:
▰ The scope of this extern variable is throughout the main
program. It is equivalent to global variable. Definition for
extern variable might be anywhere in the C program

EXAMPLE PROGRAM FOR REGISTER
VARIABLE IN C:
▰ Register variables are also local variables, but stored in
register memory. Whereas, auto variables are stored in main
CPU memory.
▰ Register variables will be accessed very faster than the
normal variables since they are stored in register memory
rather than main memory.
▰ But, only limited variables can be used as register since
register size is very low. (16 bits, 32 bits or 64 bits)

Decision Making Statements in C

Dangling else in C

Arrays 2 Dimensional Unit 2 Part 1.pdf

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Arrays 2 Dimensional Unit 2 Part 1.pdf