Lakhasly

Introduction o Computers are good only as: 1.Good Users

Programmers have three resources that they need to optimize for cost effectiveness: 1.Communicating with the Computer o Since the computer does not speak English as you do, you have to learn its system of communication or language.Good Hardware 2.Good Software 3.programmer time.computer memory 2.computer time 3.?

Introduction
• Computers are good only as:

1. Good Hardware


2. Good Software


3. Good Users

Programmers have three resources that they need to optimize for cost effectiveness:

1. computer memory


2. computer time


3. programmer time.

❛ Communicating with the Computer
• Since the computer does not speak English as you do, you have to learn its system of communication or language.
• For the computer to “understand’’ a message, its system of communication requires instructions governed by specific rules. ❜

❛ Communicating with the Computer
• The differences between instructions from one language and another are in how they are set up (Syntax).
• Syntax refers to the rules governing the computer operating system, the language, and the application.
• An error is called a bug.
• A bug must be found and corrected, a process called debugging.

❛Communicating with the Computer
• Many bugs are a result of syntax errors, but some are logic errors.
• You can find and correct most logic errors during the problem-solving process.
• You will find and correct syntax errors when you enter your program into the computer. ❜

Organizing the Solution

1. problem analysis chart : shows a beginning analysis of the problem


2. structure chart or interactivity chart : shows the overall layout or structure of the solution.


3. IPO chart : shows the input, the processing, and the output.


4. Algorithms : show the sequence of instructions comprising the solution.


5. Flowcharts : graphic representations of the algorithms.


6. Pseudocode : represents a language like solution.


7. coupling diagram :shows the relationship between the modules and the data needed for the modules.


8. Data Dictionary : lists all date variable names and their definitions.


9. UML (Unified Modeling Language) : is a basic tool when using Object Oriented Programming structure. ❜

❛ Analyzing the Problem

• good way to analyze a problem is to separate it into four parts,

1. The given data


2. The required results


3. The processing that is required in the problem


4. A list of solution alternatives

Developing the Interactivity Chart

• The next step in organizing your solution is to divide the processing into subtasks called modules.

• and then to connect these modules together to show the interaction of processing between the modules.

• There will be one module that controls the flow to most of the other modules. This will be called the Control or Main module.

Developing the IPO Chart
• The IPO (input-processing-output) chart extends and organises the information in the problem analysis chart.
• The IPO chart has four sections: the Input, the Processing, the Module Reference, and the Output

Writing the Algorithms
• After using the structure chart and the IPO chart
• The next step in organizing a solution is for the programmer to develop sets of instructions for the computer, called algorithms.

Drawing the Flowcharts
• From the algorithms the programmer develops the flowcharts, graphic representations of the algorithms.
• The algorithms and the flowcharts are the final steps in organizing a solution.

Rules for Drawing Flowcharts

1. You should write the instructions inside the blocks


2. Makes the flowchart an annotated flowchart.


3. A flowchart always starts at the top of the page and flows to the bottom


4. Use a computer program, or a template and a straightedge, to draw the flowchart.


5. Make the blocks big enough to write instructions so they can be easily read


6. Put the module number and name from the interactivity chart


7. Have plenty of paper on hand since the final copy of the flowchart normally will not be the first draft.


8. Use a pencil with a large eraser

Pseudocode
• Pseudocode is similar to the algorithm without the numbers and somewhat condensed.
• The pseudocode for the Payroll problem is given on the right hand side of the flowcharts.

Internal and External Documentation
• Internal documentation consists of remarks written with the instructions to explain what is being done in the program.
• External documentation is made up of the manuals or help menus written about the solution.