1. Copyright ©2005  Department of Computer & Information Science Introducing Computer Science: The Study of Algorithms

2. Copyright ©2005  Department of Computer & Information Science Goals By the end of this lecture you should … Understand the role of a computer as a tool in Computer Science.Understand the role of a computer as a tool in Computer Science. Understand Computer Science as the study of algorithms.Understand Computer Science as the study of algorithms. Be able to identify how algorithms are developed & evaluated.Be able to identify how algorithms are developed & evaluated.

3. Copyright ©2005  Department of Computer & Information Science The Computer as a Tool Much like the microscope does not define biology or the test tube does not define chemistry, the computer doesn't define Computer Science.Much like the microscope does not define biology or the test tube does not define chemistry, the computer doesn't define Computer Science. The computer is a tool by which Computer Scientists accomplish their goals – to solve problems.The computer is a tool by which Computer Scientists accomplish their goals – to solve problems.

4. Copyright ©2005  Department of Computer & Information Science What is Computer Science? NOT about coding or hardware or software!NOT about coding or hardware or software! Computer Science is about PROBLEM SOLVINGComputer Science is about PROBLEM SOLVING Computer Science is about DEVELOPING ALGORITHMS to solve complex problemsComputer Science is about DEVELOPING ALGORITHMS to solve complex problems

5. Copyright ©2005  Department of Computer & Information Science What is an Algorithm? An algorithm is a well-developed, organized approach to solving a complex problem.An algorithm is a well-developed, organized approach to solving a complex problem. Computer Scientists ask themselves four critical questions when they evaluate algorithms …Computer Scientists ask themselves four critical questions when they evaluate algorithms …

6. Copyright ©2005  Department of Computer & Information Science Algorithm Questions Does the algorithm solve the stated problem?Does the algorithm solve the stated problem? Is the algorithm well-defined?Is the algorithm well-defined? Does the algorithm produce an output?Does the algorithm produce an output? Does the algorithm end in a reasonable length of time?Does the algorithm end in a reasonable length of time?

7. Copyright ©2005  Department of Computer & Information Science Developing an Algorithm 1.Identify the Inputs 2.Identify the Processes 3.Identify the Outputs 4.Develop a HIPO Chart 5.Identify modules

8. Copyright ©2005  Department of Computer & Information Science 1. Identify the Inputs What data do I need?What data do I need? How will I get the data?How will I get the data? In what format will the data be?In what format will the data be?

9. Copyright ©2005  Department of Computer & Information Science 2. Identify the Processes How can I manipulate data to produce meaningful results?How can I manipulate data to produce meaningful results? Data vs. InformationData vs. Information

10. Copyright ©2005  Department of Computer & Information Science 3. Identify the Outputs What outputs do I need to return to the user?What outputs do I need to return to the user? What format should the outputs take?What format should the outputs take?

11. Copyright ©2005  Department of Computer & Information Science 4. Develop a HIPO Chart PROBLEM INPUT MODULEMODULE PROCESSES MODULEMODULE OUTPUT MODULEMODULE Hierarchy of Inputs Processes & Outputs

12. Copyright ©2005  Department of Computer & Information Science 5. Identify Relevant Modules How can I break larger problems into smaller, more manageable pieces?How can I break larger problems into smaller, more manageable pieces? What inputs do the modules need?What inputs do the modules need? What processes need to happen in the modules?What processes need to happen in the modules? What outputs are produced by the modules?What outputs are produced by the modules?

13. Copyright ©2005  Department of Computer & Information Science Summary The goal of Computer Science is to develop sound algorithms for solving complex problems.The goal of Computer Science is to develop sound algorithms for solving complex problems. An algorithm is a well-developed, detailed approach for solving a problem.An algorithm is a well-developed, detailed approach for solving a problem.

14. Copyright ©2005  Department of Computer & Information Science Summary To develop an algorithm: 1.Identify the inputs 2.Identify the processes 3.Identify the outputs 4.Develop a HIPO chart 5.Identify relevant modules