This document provides an overview of C and C++, including: - Five reasons to learn C/C++, such as industry usage and useful for other modules. - The history of C and C++, from the creation of C at Bell Labs in the 1970s to the development of C++ in the 1980s. - The aims of C, such as ability to write low-level code and efficiency, versus the aims of C++ which grew from C while keeping some similar aims. - The differences between procedural and object-oriented languages, and how C++ allows both paradigms while C is purely procedural. - The similarities and differences between C and C++ in

1. ICIT COMPUTER
INSTITUE

2. This lecture
• Five reasons to learn C/C++
• History of C and C++
• Aims of c and c++
• Procedural languages & oo languages
• Similarities between c & c++
• Differences between c & c++
• Compilation, Linkage and Running
• Packages
• Functions

3. Five reasons to learn C & C++?
1. (Still) utilised in industry
Why so popular? (after so long)
2. Choose the appropriate tool for the task
Understand the Java vs C/C++ differences
3. More programming practice
Much is common across languages
4. Much is VERY similar to Java
Easier to learn: much will be familiar to you
5. Useful for other modules
And projects

4. The history of C/C++
In Bell Labs, ‘B’ language created, based on BCPL
1971-1973 : Dennis Ritchie extended ‘B’ to create ‘C’
Main features of C developed over this time
1973-1980 : New features were added
C needed to be standardised!
1979 : Bjarne Stroustrup (Bell labs) extended C to make ‘C with classes’
1982 : ‘K&R’ (Kernighan and Ritchie) unofficial C ‘standard’
1983 : ‘C with classes’ renamed C++, features still being added
1989 : ANSI standard C (started in 1983!) (=> ISO standard in 1990)
Differs in some ways from K&R ‘C’ and is often named ‘C89’
Together with Amendment 1, forms ‘C’ element of ‘C++’
1990s : C++ took centre stage (Standardisation progressing)
1994 : Standard Template Library makes it into the ISO standard C++
(Some template implementation arguments ongoing as late as 2003)
1995 : Java released by Sun
1998 : ISO standard C++ ratified (C++98)
1999 : New version of C standard (C99) (Differs from C++)
We will concentrate on C89 and C++

5. The aims of C and C++
• C came first : with specific design aims
• Ability to write low-level code (e.g. O/S)
• Speed and efficiency
• Ease for programmers
• Rather than non-programmers
• C++ grew from C : kept some similar aims

6. Is C++ O.O. or Procedural
• C is procedural (no classes, hard to do OO)
• C++ will let you do either
• You CAN write procedural C++
• Or you can write object oriented C++
• Or mix both together (often a bad idea)
• C++ also adds a lot of non-OO features
• e.g. templates, new/delete, operator overloading, …
• Useful for procedural programming as well

7. Object oriented vs Procedural
• My view:
• Procedural or object oriented are ways of thinking
• How do you want to think of your program?
• A lot of communicating objects
• Or ‘do this then this then this…’
• Whichever you use: (within a thread)
• Functions are still called one at a time
• And operations are executed one at a time

8. OO – a good or bad thing?
• Object oriented techniques can hide some of the
complexity (a good thing?)
• Make it easier to understand a program (?)
• Make it easier to structure a large program (?)
• Some facilities hide what is actually happening, to
simplify things (bad?)
• We are going to look at C/C++, not object oriented
design/programming
• Many courses start with object oriented C++

9. Similarities
• same built-in data types
• same compiler preprocessor
• handles #include & #define
• same built-in operators on primitive types
(+-/*……)

10. Similarities (cont.)
• Same built-in control structures
• if, for, while, switch ….
• must have a function names “main” to
determine where the program starts
• functions are defined the same way
• programs can be split up into separate files

11. Differences
• in C all code exists in function and the
paradigm is that you manipulate data with
functions
• in C++ classes are used to model the
behavior of data objects, behavior is
represented by functions and those
functions are used to modify the object’s
data

12. Differences (cont.)
• in C a struct is used to make an aggregate type
and cannot have associated functions
• in C++ struct there may be associated (part of
the struct) functions to process the data
• in C I/O is accomplished via library functions,
in C++ it is done by using object methods.

13. Differences (cont.)
• C++ has function overloading (two functions may
have the same name), in C function names must be
unique.
• C++ has operator overloading (operators can be
redefined to do other things)
• C++ uses “nbew” and “delete” for dynamic memory
management, C uses “malloc” and “free”

14. Machine Language
• A system of instructions and data directly
executed by a computer’s central processing unit
• Machine language is represented by bits (binary
digits) i.e. 0s and 1s.
• Example: 00111010

15. Assembly Language
• More readable version of machine language
• Uses mnemonic codes to refer to machine code
instructions
• Example:
INC A (Increment Register A), DEC B (Decrement
Register B)

16. High Level Language
• Easier to use and more portable across platforms
• Represented using English like statements
• Examples: Basic, Fortran, Cobol, C.

17. Compilation and Execution
of C++ programs
STEP 1:- Compilation
Example.cpp This code is written in c++
(source code) language understood by
programmer.
Example.obj
code is converted into a
(object code) machine readable form
(machine language).

18. STEP 2:- Linking
The machine readable code
Example.obj Cs.lib
(object code) (library files)
and library files that are
included in the program are
linked together.
Example.exe
There by we get an .exe file
(executable file) that can be executed.

19. • STEP 3:- Execution
Statements in the program will be executed 1 by 1
And produce the results

20. THANK - YOU