The Program Development Cycle

Grade 10 – Computer Programming

Program Development Cycle

Modern software developers base many of their techniques on traditional approaches to mathematical problem solving.One such approach is based on the how engineers solve problems.

Program Development Cycle

Engineers must:

• Design a solution to a problem

• Implement the solution

• Test the solution

• Fix any errors in the solution

Program Development Cycle

This approach can be used in computer programming:

• Design a solution to a problem (design a program)

• Implement the solution (code the program )• Test the solution (test the program) • Fix the solution (debug the program)

Program Development CycleOnce the software is working, improvements

can be designed into the system. This leads back to design, creating a four-phase cycle.

Program Development Cycle

Program Development Cycle

Designing the StructureFind a logical sequence of precise steps that

solve the problem (aka the algorithm). The logical plan may include flowcharts, pseudocode, and top-down charts.

Program Development Cycle

Design the interface – Select objects (text boxes,

buttons, etc.).

Determine how to obtain input and how the output will

be displayed. Objects are created to receive input and display

output. Appropriate menus, buttons, etc. are created to allow

user to control the program

Program Development Cycle

Program Development Cycle

The program development cycle’s

code phase includes translating a

software design into a particular

language, and then entering that

language on the computer.

During this stage that program is

written.

Program Development Cycle

Program Development Cycle

Testing is the process for finding errors.

Debugging is the process for correcting errors

Does the new method do what it is supposed to do?

This is known as a test for correctness. Tests for

correctness measure whether the program meets the

original specifications.

Program Development Cycle

Testing can be rather complicated:

Is the method reasonably efficient? How much time

does it take for the method to complete its task, and

how much space does it use?

Program Development Cycle

Testing can be rather complicated:

Does the method have any undesirable side effects?

How does one program affects the performance of

another program, or one method affects another

method?

Program Development CycleProgrammers perform unit tests and integration tests.

A unit test checks to see if a method works as expected all by itself.

An integration test checks to see if a method works in combination with other methods.

Program Development Cycle

Program Development Cycle

The causes of any problems discovered during testing need to be isolated. Here unit tests are most helpful.

Once you know the cause, you can develop a plan for fixing the problem, modify the necessary methods, and then test again.

Program Development Cycle

Documentation is necessary to allow another programmer or non-programmer to understand the program. Internal documentation, known as comments, are created to assist a programmer. An instruction manual is created for the non-programmer. Documentation should be done during the coding stage.

Documentation