上海交通大学：《Computational Thinking and Approach》教学资源（课件讲稿）Lecture02

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY Computational Thinking and Approach Lecture 2 Dr.Jialiang LU Jialiang.lu@situ.edu.cn

Computational Thinking and Approach Lecture 2 Dr. Jialiang LU Jialiang.lu@sjtu.edu.cn 1

上游充通大学 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY Variables,Expression and Statements Elements of Programs 。Comments 。Output Statements Assignment Statements ·Compound Statements Goode Programming Style 2

Variables, Expression and Statements • Elements of Programs • Comments • Output Statements • Assignment Statements • Compound Statements • Goode Programming Style 2

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process The process of creating a program is often broken down into stages according to the information that is produced in each phase. 3

The Software Development Process • The process of creating a program is often broken down into stages according to the information that is produced in each phase. 3

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process ·Analyze the Problem Figure out exactly the problem to be solved. Try to understand it as much as possible. 4

The Software Development Process • Analyze the Problem Figure out exactly the problem to be solved. Try to understand it as much as possible. 4

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process Determine Specifications Describe exactly what your program will do. Don't worry about how the program will work,but what it will do. Includes describing the inputs,outputs,and how they relate to one another. 5

The Software Development Process • Determine Specifications Describe exactly what your program will do. – Don’t worry about how the program will work, but what it will do. – Includes describing the inputs, outputs, and how they relate to one another. 5

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process e Create a Design Formulate the overall structure of the program. This is where the how of the program gets worked out. You choose or develop your own algorithm that meets the specifications. 6

The Software Development Process • Create a Design – Formulate the overall structure of the program. – This is where the how of the program gets worked out. – You choose or develop your own algorithm that meets the specifications. 6

上游充通大学 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process 。Implement the Design Translate the design into a computer language. -In this course we will use Python. 7

The Software Development Process • Implement the Design – Translate the design into a computer language. – In this course we will use Python. 7

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process Test/Debug the Program Try out your program to see if it worked. If there are any errors (bugs),they need to be located and fixed.This process is called debugging. -Your goal is to find errors,so try everything that might "break"your program! 8

The Software Development Process • Test/Debug the Program – Try out your program to see if it worked. – If there are any errors (bugs), they need to be located and fixed. This process is called debugging. – Your goal is to find errors, so try everything that might “break” your program! 8

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY The Software Development Process e Maintain the Program - Continue developing the program in response to the needs of your users. In the real world,most programs are never completely finished-they evolve over time. 9

The Software Development Process • Maintain the Program – Continue developing the program in response to the needs of your users. – In the real world, most programs are never completely finished – they evolve over time. 9

上游充通大 ParisTech SHANGHAI JIAO TONG UNIVERSITY INSTITUT DES SCIENCES ET TECHNOLOGIES PARIS INSTITUTE OF TECHNOLOGY Example Program:Temperature Converter Analysis-the temperature is given in Celsius, user wants it expressed in degrees Fahrenheit. -F=(9/5)*C+32 。Specification Input-temperature in Celsius Output-temperature in Fahrenheit Output 9/5(input)+32 10

Example Program: Temperature Converter • Analysis – the temperature is given in Celsius, user wants it expressed in degrees Fahrenheit. – F=(9/5)*C+32 • Specification – Input – temperature in Celsius – Output – temperature in Fahrenheit – Output = 9/5(input) + 32 10