Summary of the Lecture

Transcription

1 Summary of the Lecture 1 Introduction 2 MATLAB env., Variables, and format MATLAB function, arrays and operations Algorithm and flowchart M-files: Script and Function Files 6 Structured Programming Conditional statements 7 Structured Programming Loops 1

2 Dr. Zarina Ab Muis Faculty of Chemical Engineering Universiti Teknologi Malaysia, UTM Johor, Johor Bahru, Malaysia 2

3 Topic Outcomes Week Topic Topic Outcomes 9-11 Relational and logical operators The if end structure The if else end structure The if elseif else end structure The switch case statement Case study in chemical engineering Understand and apply the relational and logical operators Write program with if...end structure Write program with switch-case statement Solve chemical engineering problem related with program consist conditional statements 3

4 Outline of the Lecture Introduction Relational and Logical Operators The If end structure The If else end structure The If elseif else end structure The switch case statement 4

5 Introduction What is Structured Programming? Structured programming allows MATLAB to make decisions or loops based on conditions of the program. Decisions in MATLAB are based on the result of logical and relational operations and are implemented with if, if else, and if elseif structures. 5

6 Structured programming If end == OR ( ) >= AND (&) NOT (~) If-elseend switchcase < 6

7 Outline of the Lecture Introduction Relational and Logical Operators The if end structure The if else end structure The if elseif else end structure The switch case statement 7

8 Relational and Logical Operators Relational Operators: Compare 2 numbers by determining whether a comparison statement is TRUE (1) or FALSE(0) E.g: 10 < 15 Logical Operators: Examines true/false statements and produce result that is TRUE(1) or FALSE(0) E.g: AND (&) 8

9 Relational Operators < Less than > Greater than No Space between two signs <= >= Less than or equal to == Equal to Greater than or equal to ~= Not equal to 9

10 Relational Operators When Two numbers (X and Y) are compared: X >= Y If the comparison according to RO is TRUE, the result is 1 If the comparison is FALSE, the result is 0 10

11 Relational Operators If X and Y are scalars, the result is a scalar 1 or 0 Exercise: 5 >= 10 ans= 0 i. 13<13 ii > 10 iii. 5~=5.1 iv. 1<2<3 v. 12<15>10 vi. 12-4<5x3<4 11

12 Relational Operators If X and Y are arrays (same size), the comparison is done element-by-element, and the result is a logical array of the same size X=[2 8 10] Y=[1 8 13] X >= Y ans= [1 1 0] 12

13 Relational Operators Exercise Given: v=[ ] and u=[ ] i. u< v ii. Z=v>=u iii. u==abs(v) iv. Z>=u+v Ans: Ans: Ans: Ans:

14 Relational Operators If X is scalar, Y is array. X is compared with every element in the array, and the result is a logical array of the same size as Y. X=10 ; Y=[1 13 8] X >= Y ans= [1 0 1] 14

15 Relational Operators Exercise Given: D=[4-1 7 ; ; ]. Checks which elements in D are smaller than or equal to 3. Assigns the results to matrix Z. Ans: 15

16 Logical Operators AND (&) E.g: X & Y Operates on 2 operands (X and Y) If both X and Y are true =1, otherwise false = 0 OR ( ) E.g: X Y Operates on 2 operands (X and Y) If either one, or both are true = 1, otherwise (both false) = 0 NOT (~) E.g: ~X Operates on 1 operand (X) Give the opposite of X; true=1 if X is false, and false=0 if X is true 16

17 Logical Operators TRUE = Nonzero number FALSE = Zero number Logical operators can be used with scalars and arrays 17

18 Logical Operators Exercise Given: v=[ ] and u=[ ] i. ~~u ii. v & u iii. u(3) v iv. v==~u Ans: Ans: Ans: Ans:

19 Outline of the Lecture Introduction Relational and Logical Operators The if end structure The if else end structure The if elseif else end structure The switch case statement 19

20 Decision Decisions are made in MATLAB using if structures, which may also include several elseif branches and possibly a catch-all else branch. Deciding which branch runs is based on the result of conditions which are either true or false. If an if tree hits a true condition, that branch (and that branch only) runs, then the tree terminates. If an if tree gets to an else statement without running any prior branch, that branch will run. 20

21 The if end structure A command that allows MATLAB to make decision of whether to execute a group of commands or to skip these commands. False Flowchart if statement True Commands end MATLAB program If conditional expression A group of MATLAB commands end MATLAB program 21

22 The if end structure Exercise 6.1: Write a program in a script file that calculate the parking fees at a shopping mall. The first 1 hour is free. If more than 1 hour, the customer needs to pay RM1.00 for the first hour and RM0.50 for every additional hour. The program asks the user to enter the duration (in hour). The program should display fees for parking lot. Run the program for the following cases: i) 0.5 h ii) 1 h iii) 3 h 22

23 Outline of the Lecture Introduction Relational and Logical Operators The if end structure The if else end structure The if elseif else end structure The switch case statement 23

24 The if end structure A command that allows MATLAB to make decision of whether to execute a group of commands or to skip these commands. False Flowchart if statement True Commands end MATLAB program If conditional expression A group of MATLAB commands end MATLAB program 24

25 The if-else-end structure False Commands Group2 Flowchart if statement True Commands Group1 end MATLAB program if conditional expression Group1 of MATLAB commands else end MATLAB program Group2 of MATLAB commands 25

26 Example: if-else-end Write a program to calculate Z according to L value. If L less than or 10, Z=Lx10. Otherwise, return an error msg. Start L False 1. Start if L <=10 2. Give input L 3. Check L is less or equal to 10, if yes go to step 4. if No, go to step 6 4. Calculate Z=Lx10 5. Print Z 6. Print Error!. L is not in the specified range 7. Stop Print Error!. L is not in the specified range Z=L*10 Print Z End True 26

27 The if-elseif-elseend structure False Commands Group 3 False elseif statement True Commands Group 2 Flowchart if statement True Commands Group 1 end MATLAB program if conditional expression elseif else end MATLAB program Group 1 of MATLAB commands Group 2 of MATLAB commands Group 3 of MATLAB commands 27

28 Example: if-elseif-else-end Write a program to calculate Z according to L value. If L less than or 10, Z=Lx10. But, if L in the range of 15 to 11, Z must be calculated using Z=Lx Otherwise, return an error msg. 1. Start 2. Give input L 3. Check L is less or equal to 10, if yes go to step 4. if No, go to step 6 4. Calculate Z=Lx10 5. Print Z 6. Check L is less than or equal to 15 and greater than 10, if YES go to step 7, if NO go to step Calculate Z=Lx Print Z 9. Print Error!. L is not in the specified range 10. Stop 28

29 Exercise 6.2: If-else-end Write a program in a script file that calculate the parking fees at a shopping mall. If customer parked less than 1 hour, parking fee is free. If more than 1 hour, the customer needs to pay RM1.00 for the first hour and RM0.50 for every additional hours. The program asks the user to enter the duration (in hour). The program should display fees for parking for each cases including free parking. Run the program for the following cases: i) 0.5 h ii) 1 h iii) 3 h iv) 5.5 h 29

30 Exercise 6.3: Figure 1 30

31 Outline of the Lecture Introduction Relational and Logical Operators The if end structure The if else end structure The if elseif else end structure The switch case statement 31

32 The switch-case statement Another method to direct the flow of a program It provides a means for choosing one group of commands for execution out of several possible groups. The first line is the switch command Switch switch expression Several case commands Scalar/ string/ math expression After last case, there is optional for otherwise command Last line must be an end statement 32

33 The switch-case statement MATLAB program switch switch xpression case value1 Group 1 of commands case value2 Group 2 of commands case value3 otherwise end MATLAB program Group 3 of commands Group 4 of commands 33

34 The switch-case statement Example: To calculate the area for different cases Case 1: area=lxw Case 2: area=pi*d 2 Otherwise return error msg 34

35 Recap of the previous lecture 35

36 The switch-case statement Write a program to convert temperature in Celcius to either Kelvin or Fahrenheit using switch-case statement. The output might look like this 36

37 Tutorial 6.1 Body Mass Index (BMI) is a measure of obesity. In standard units, it is calculated by the formula BMI Below 18.5 Classification Underweight 18.5 to 24.9 Normal 25 to 29.9 Overweight 30 and above Obese Write a program to calculate the BMI of a person. The program asks the person to enter his or her weight(kg) and height(m). The program display the result of the BMI value and the BMI classification. i) A person 160 cm and 65 kg ii) iii) A person 110 cm and 45 kg Your BMI 37

38 Tutorial 6.2 Write a computer program in a script file that determines the test grade for a student. Display the results of mark and grade. Execute the program for the following cases a) 53 b) 78 c) 80 38

39 Tutorial 6.3 Modify the program developed in Tutorial 6.2 to determine the final grade of a subject from the assessment distribution below. Display the results of final mark and grade for all students Assessment Total Mark Percentage Quiz Test Test Final Name Quiz Test 1 Test 2 Final Grade Ahmad Wan Anis Najwa

40 Exercise 6.4 Write a user-defined MATLAB function, with two input and two output arguments that determines the height in centimeters (cm) and mass in kilograms (kg)of a person from his height in inches (in.) and weight in pounds (lb). (a) Determine in SI units the height and mass of a 5 ft. 15 in. person who weight 180 lb. (b) Determine your own height and weight in SI units. 40

41 Assignment Write a user-define program for calculating your CPA and CGPA for every semester. Input of the program can be either mark or grade Evaluation Criteria: Convergence: Creativity: Output/Results: User friendly program 41