Introduction to Information and Computer Science Computer Programming Lecture c This material (Comp4_Unit5c), was developed by Oregon Health and Science University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number IU24OC

Computer Programming Learning Objectives Define the purpose of programming languages. (Lecture a) Differentiate between the different types of programming languages and list commonly used ones. (Lecture a) Explain the compiling and interpreting process for computer programs. (Lecture b) Learn basic programming concepts including variable declarations, assignment statements, expressions, conditional statements and loops. (Lectures c, d) Describe advanced programming concepts including objects and modularity. (Lecture e) 2 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Programming Constructs Declarations (variable/constant) Assignment Statements Expressions Input and Output (I/O) Statements Control Structures Data Structures Modules –Procedures –Methods –Objects 3 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Variables Variables store data –Implemented as memory locations –Referred to by a name Data stored by a variable is its value –Value is stored in the memory location Its value can be changed (i.e., variable) Similar construct for constants (value cannot change) 4 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Data Type Every variable and constant has a data type –Knows how much memory to use –Knows how to handle data Common data types –Integer –Floating point –Character –Boolean 5 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Java Data Types Java is strongly typed –All variables must be declared with a type Java data types –Primitive int, double, float, char, boolean –Class String Other user/library defined types 6 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Declaration Statements Variable declarations give the name and type int age; –A variable’s type determines what kinds of values it can hold –A variable must be declared before it is used in Java Java examples double bmi; char gender; boolean completed; Note: Most Java statements end with a semicolon 7 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Assignment Statements An assignment statement is used to assign a value to a variable age = 42; The “equal sign” is the assignment operator Options include: –“The variable age is assigned the value of 42” – “ age is assigned 42” –" age gets 42" 8 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Values and Expressions Values can be literals such as 'f' Values can be expressions such as weight/2 5 + age 3 + 2/5 * 15 n*m 9 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Arithmetic Expressions Arithmetic expressions contain operators and evaluate to a value +, -, *, / Order of evaluation is determined by precedence 1.Expressions in parentheses evaluated first 2.Then *,/ 3.Then +, - 4.Same order of precedence evaluated left to right 10 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Expression Examples bmi = weight / (height * height); age = age + 1; tricky = * 2; What is the value of tricky after the assignment? 11 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Input and Output All programming languages support data input –Keyboard –Files All programming languages support data output –Screen –Files 12 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Screen Output in Java Output is done using System.out.print() Does not include line return System.out.println() Includes line return Code examples System.out.println("Hello World!"); System.out.print("My name is "); System.out.println(name); System.out.println(gender); 13 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Keyboard Input in Java Keyboard input is more complicated Must include package java.util Must create object of Scanner class Scanner keyboard = new Scanner(System.in); Use methods in Scanner class next(); nextLine(); nextDouble(); next Int(); Example age = keyboard.nextInt(); 14 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Exercise Write a Java program that calculates BMI (body mass index) Read in weight (kg) Read in height (m) Calculate BMI Output BMI 15 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Program Design Prompt user for weight in kg Read in weight Prompt user for height in m Read in height Calculate BMI BMI = weight/(height * height) Output BMI 16 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

1.import java.util.*; //import package for keyboard input 2. public class CalcBMI //Start of class and program 3. { 4. public static void main(String[] args) //main 5. { 6. double bmi, weight, height; //variables 7. Scanner keyboard = new Scanner(System.in); //input System.out.println("Welcome to the BMI calculator"); 10. System.out.println("Enter weight in kg"); 11. weight = keyboard.nextDouble(); 12. System.out.println("Enter height in m"); 13. height = keyboard.nextDouble(); 14. bmi = weight/(height*height); 15. System.out.print("BMI is "); 16. System.out.println(bmi); 17. } 18. } 17 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Sample Output Welcome to the BMI calculator Enter weight in kg 68 (green) Enter height in m 1.72 (green) BMI is Note: Values in green are entered by the user 18 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Computer Programming Summary – Lecture c Programming languages consist of common constructs Variables store data and have a data type Variables can be assigned values or expressions Java provides statements for variable declarations, assignments and expressions Java provides statements and classes for input and output 19 Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c

Computer Programming References – Lecture c References Eck, David. (2011) Introduction to Programming Using Java, Sixth Edition. [updated 2011 Jul 18; cited 2011 Nov 13]: Available from: Morley Deborah, Parker Charles S. (2010). Chapter 13: Program Development and Programming Languages. In: Understanding Computers Today and Tomorrow.12 th ed. Boston: Course Technology. Parsons JJ, Oja D. (2010). Chapter 12: Computer Programming. In: New Perspectives on Computer Concepts 2011: Comprehensive. 13th ed. Boston: Course Technology. The Java Language: An Overview. [Webpage]. c [updated 2007 Dec 17; cited 21 March 2011]. Available from: Sierra Kathy, Bates Bert. (2009). Head First Java, Second Edition. O’Reilly Media. Images Slide 16: Scale Image [image on the Internet]. c 2009 [Updated 4/2/2009; cited 11/12/2011]. Available from: Health IT Workforce Curriculum Version 3.0/Spring 2012 Introduction to Information and Computer Science Computer Programming Lecture c