1.2 Computer systems  (Page 7/8)

Pros and Cons of Flowcharts

In fact, flowcharts are not very useful.The process of writing an algorithm in the form of a flowchart is just too cumbersome, and then converting this graphical form into code is not straight forward

However, there is another kind of flowcharts – called Structured Flowcharts – that may be better suited for software developers.

The good thing about flowcharts is that their symbols are quite intuitive and almost universally understood. Their graphical nature makes the process of explaining an algorithm to one’s peers quite straightforward.

Pros and Cons of Pseudocode

Pseudocode are quite suitable for software development as it is closer in form to real code.One can write the pseudocode, then use it as a starting point or outline for writing real code.

Many developers write the pseudocode first and then incrementally comment each line out while converting that line into real code.Pseudocode can be constructed quite quickly as compared with a flowchart.

Unlike flowcharts, no standard rules exist for writing pseudocode

To design an algorithm, the following characteristics are very

• Exactness
• Effectiveness
• Guaranteed termination
• Generality

The concept of structured programming says that any programming logic problem can be solved using an appropriate combination of only three programming structures,

1.Sequence : a sequence of instructions that are executed in the precise order they are written in

2. Conditional : Select between alternate courses of action depending upon the evaluation of a condition

Loops : Loop through a set of statements as long as a condition is true

Programs and programming languages

Programs

A computer program is an algorithm written for a computer in a special programming language.

Programming languages

A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. It is defined through the use of syntactic and semantic rules, to determine structure and meaning respectively.

Programming languages are used to facilitate communication about the task of organizing and manipulating information, and to express algorithms precisely.

There are large number of programming language in use. We can identify three type of programming languages : machine languages, assembly languages, high-level languages.

Machine Languages

Machine code or machine language is a system of instructions and data directly executed by a computer's central processing unit. Machine code is the lowest-level of abstraction for representing a computer program.Instructions are patterns of bits with different patterns corresponding to different commands to the machine. Machine code has several significant disadvantages : very difficult for a human to read and write, a program written on one computer cannot run on a different computer, so it cannot be used to write large program or program intended to run on different machines.

Assembly Languages

An assembly language is a low-level language for programming computers. It implements a symbolic representation of the numeric machine codes and other constants needed to program a particular CPU architecture.