C++ programming

this article is related with my previous topic , which was about c++ programming , here i m going to discuss that article more.

C++ programming

Std::cout

Standard output stream object

“Connected” to the screen

std:: specifies the "namespace" which cout belongs to

std:: can be removed by the use of using statements

with the help of using statement we can write cout instead of std::cout as we would observe in the next program.

<< 

Stream insertion operator 

Value to the right of the operator (right operand) inserted into output stream (which is connected to the screen)

std::cout << “Welcome to C++!\n”;

Indicates that a “special” character is to be output 

There are multiple ways to print text. Following are some more examples.

output 

Testing and debugging 

Bug

A mistake in a program

Debugging

Eliminating mistakes in programs

Term used when a moth caused a failed relay on the Harvard Mark 1 computer.  Grace Hopper and other programmers taped the moth in logbook stating:          “First actual case of a bug being found.”

Program errors

Syntax errors

Violation of the grammar rules of the language

Discovered by the compiler

Error messages may not always show correct location of errors

Run-time errors

Error conditions detected by the computer at run-time

Logic errors

Errors in the program’s algorithm

Most difficult to diagnose

Computer does not recognize an error

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computer programming in C++

in this article and in the incoming next articles i will cover all those topic , that will help you in writing a program , that is used in many designing eg in making calculator , logical operation etc , here its some describation of programming and a computer, or some mobile etc these programe are built in a device and come by default.

What is computer?

Computer
A device capable of performing computations and making logical decisions
A machine that manipulates data according to a list of instructions.
A programmable device that can store, retrieve, and process data.

Computer programs

Sets of instructions that control a computer’s processing of data

Hardware
Physical part of the computer
Various devices comprising a computer
Examples: keyboard, screen, mouse, disks, memory, CD-ROM, and processing units

Software
A collection of computer programs, procedures and documentation that perform some tasks on a computer system
Programs that run a computer

Computer organization

There are Six logical units in every computer:
Input unit
Obtains information (data and computer programs)  from input devices (keyboard, mouse)
Output unit
Outputs information to output device (screen, printer) or to control other devices.
Memory unit
 Rapid access, low capacity, stores input information
Arithmetic and logic unit (ALU)
Performs arithmetic calculations and logic decisions
Central processing unit (CPU)
Supervises and coordinates the other sections of the computer
Secondary storage unit
Cheap, long-term, high-capacity storage, stores inactive programs

Computer languages

Computer languages are divided into three types.
Machine languages
Machine language is machine dependent.
Strings of numbers giving machine specific instructions
Example:
+1300042774 +1400593419 +1200274027

Assembly languages

English-like abbreviations representing elementary computer operations (translated via assemblers)
Example:
  LOAD BASEPAY ADD OVERPAY STORE GROSSPAY
     Translator programs called assembler were developed to convert assembly language programs to machine language programs at computer speed.

High-level languages

Similar to everyday English, use mathematical notations (translated via compilers)
Example:
grossPay = basePay + overTimePay
C, C++ are the most widely used high level languages. Some other examples are
FORTRAN (formula translator)
         Used in scientific and engineering applications
COBOL (common business oriented language)
         Used to manipulate large amounts of data
Pascal
          Used to teach structured programming
Translator programs called Compilers converts high-level language programs into machine language

Object technology

Models the real world with groups of interacting objects

Object technology is a packaging scheme that helps create Meaningful software units
Date objects, time objects, paycheck objects, invoice objects, audio objects, video objects, file objects, record objects, etc.
Any noun can be represented as an object
Reusable software components that model real world items
More understandable, better organized and easier to maintain than procedural programming
Favor modularity
Java and C++ are popular object oriented languages.
Allows development of more error free and reliable software.

Basics of C++ environment 

Phases of C++ Programs    
       to be executed        

      1     EdiD
      2   process
      3    Compile
      4   Link
       5   Load
        6  Execute

Program organization

Program statement
Definition
Declaration
Action

Executable unit
Named set of program statements
Different languages refer to executable units by different names
Subroutine:  Fortran and Basic
Procedure: Pascal
Function : C++

C++ programming 

C++ program
Collection of  definitions, declarations and functions
Collection can span multiple files

Advantages
Structured into small understandable units
Complexity is reduced
Overall program size decreases
Pseudo code
Artificial, informal language used to develop algorithms
Similar to everyday English

Not executed on computers
Used to think out program before coding
Easy to convert into C++ program
Only executable statements
No need to declare variables
Algorithm
A sequence of precise instructions which leads to a solution
Program
An algorithm expressed in a language the computer can understand

program design 

Programming is a creative process

Program Design Process

Problem Solving Phase

Result is an algorithm that solves the problem

Implementation Phase

Result is the algorithm translated into a programming language

Program solving phase

Be certain the task is completely specified

What is the input?  

What information is in the output?  

How is the output organized?

Develop the algorithm before implementation

Experience shows this saves time in getting your program to run.

Test the algorithm for correctness

Implementation phase

Translate the algorithm into a programming language

Easier as you gain experience with the language

Compile the source code

Locates errors in using the programming language

Run the program on sample data

Verify correctness of results

Results may require modification of the algorithm and program

main program

 

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