MODULE1-INTRODUCTION.pptx-COMPUTER PROGRAMING

Computer programming

1. COMPUTER PROGRAMMING 1 By: MARYGRACE T. AGPAOA, MIT

2. C#/C SHARP C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework. C# has roots from the C family, and the language is close to other popular languages like  C++  and  Java .

3. Programming Languages 3 levels High level language – English like language Translator s – convert the programmer/source codes into machine codes Compiler Interpreter Example: python, java, C#, c++ , html, visual basic Middle level Language – combination of English terms and binary codes Translator – Assembler Example: Assembly Language Low level language – binary codes – are a combination of the digits 0 and 1. 10001100 Directly read by the computer Binary language – 0 – false, off 1 – true, on

4. USES Mobile applications Desktop applications Web applications Web services Web sites Games VR Database applications And much, much more!

5. Definition of a Program Programming is the creation of an ordered set of instructions to solve a problem with a computer. The instructions sometimes referred to as codes make up a computer program. Computer Program is a collection of instructions that performs a specific task when executed by a computer designed by a computer programmer. Programming needs a language called Programming Language to communicate with computers.

6. Steps in the Programming Process Problem definition You need to understand the problem before you can expect to get a correct solution to the problem. What information (inputs), is given to you to use to solve the problem? What will the solution (outputs) of the problem, look like? What calculations (processes), will be used to change the input information into the desired output?

7. Example: Problem: Write a program to input 2 integers and display their sum. Input/s: 2 integers Process: add 2 integers Output/s: Print sum

8. Steps… Algorithm design Break the problem into the steps of what must be done to solve the problem. List what tasks need to be done to solve the problem. An English outline is a good tool for doing the job. Expand the outline into a complete solution. It should list all the steps that need to be done, in the correct order they need to be done in.

9. Steps… Desktop testing In this step, you pretend to be a computer and execute the steps in the algorithm. Be careful to follow the algorithm exactly! Don't add steps, or leave out any steps. Don't rearrange the steps. If you don't get the right answer to the problem, then you have an error in the algorithm. Fix it and try again until you get the right answer.

10. Steps… Coding Once the algorithm, or complete outline works correctly, you need to translate the algorithm into a computer language that your computer understands.

11. Steps… Testing and debugging Now, enter the program into the computer, enter some test data, and have the computer execute the program. If you get the correct answer to the problem, the program works! Otherwise, look for errors in the program and try again. 2 types of error Syntax error – error on how you write the program – ex. Missing quotes, wrong spelling, no semi colon No output displayed Logical error – error on the logic of the program. It displays incorrect output

12. Steps… Documentation (optional) You may want to write a user’s manual in order for users of your program will know how to use it properly and step by step. Once the program works correctly, you want make sure the documentation is up to date and be ready to maintain the program. Good programs get better during the life-time as people think of better way to do things and additional tasks the program might do.

13. Program Logic Formulation Logical reasoning – the use of logical thinking in order to find results or draw conclusions

14. Algorithm An algorithm is a logical sequence of steps for solving a problem that can be translated into a computer program. Two ways of implementing an algorithm: 1. Pseudocode 2. Flowchart

15. Flowcharts and Pseudocodes A pseudocode is an artificial and informal language that helps programmers develop algorithms. It is usually a combination of English words and some keywords of a programming language. A flowchart is a diagram that represents the sequence of operations in a process. It is a graphic representation of an algorithm.

16. Problem: create an algorithm to compute the sum of two integers Input/s: first number, second number Process: add the two numbers Output: sum Pseudocode: 1. Enter first number and second number 2. Compute the sum, sum = first number + second number 3. Print sum

17. Start int A=0, B=0, sum = 0 Enter “First Number”, A Enter “Second Number”, B sum = A+B Print sum end Start int b = 0, h = 0, Area = 0 Enter “base”, b Enter “height”, h Area = b * h / 2 Print Area end

18. Problem#2: Create an algorithm to compute the area of a triangle Input/s: base, height Process: A = b*h/2 Output: Area of the triangle Pseudocode: 1. Enter base and height 2. Compute the Area, Area = base * height/2 3. Print Area

19. Flowcharting Symbols Termina l. Marks the starting or ending point of the flowchart Oval START END

20. Flowcharting Symbols Rectangle Process . Represents a single step, or an entire sub-process within a larger process SUM = NUM1+NUM2 AVERAGE = SUM/2

21. Flowcharting Symbols Parallelogram Input/Output . Represents material or information entering or leaving the system INPPUT NUM1, NUM2 PRINT SUM, AVERAGE

22. Flowcharting Symbols Circle ON-PAGE Connector . Indicates that the flow continues where a matching symbol has been placed A A

23. Flowcharting Symbols Arrow

24. Flowcharting Symbols Off-Page Connector . Indicates that the process continues off page Pentagon CURRENT PAGE OTHER PAGE P1 P1

25. Flowcharting Symbols Decision. A branching point; lines representing different decisions emerge from different points of the diamond Diamond AGE>=18? Y N PRINT “Qualified to Vote” PRINT “Not Qualified to Vote ”

26. Flowcharting Symbols Initialization . Used to prepare components of a program Hexagon int num1=5,num2=3, sum=num1+num2; ave = sum/2; sum=0, ave = 0

27. Notations commonly used in Flowcharting Notation Meaning + - * / ** ( ) = >  <  < > > = < = Y N Addition Subtraction Multiplication Division Exponentiation Grouping Equal to Greater than Less than Not Equal to Greater than or Equal to Less than or Equal to Yes No 2+3 = 5 3-2 2*3 4/2 2**2 (2+3) * 2 X=Y 5>2 5<6 5<>6 6>=6 5<=7

28. Rules of Precedence In other words, the precedence is: Parentheses (simplify inside 'em) Exponents. Multiplication and Division (from left to right) Addition and Subtraction (from left to right)

29. BOOLEAN Expressions 4+20/5-4*2 4+4-4*2 4+4-8 8-8 4 2 + 20 /4*2 3 4**2 +20/4*2**3 16+20/ 4 * 8 16+5*8 16+40 56

30. YOUR TURN 100/4*2 – 10+70 (48+75) * 10 / 20 8 + (4*(50/25) – 20) [3*(3 3 – 20) - 3 2 ] / 3 Z= A*C/2+100 –(A B +B A ), where A=4,B=5, C=2

31. Variable a storage location capable of containing a certain type of data that can be modified during program execution. These variables will represent certain values Example: num1,sum,ave,total, name, address Num1 = 5, name=“Joey”, address = “Tuguegarao”

32. Rules of Drawing Flowcharts for Algorithms All boxes of flowcharts are connected with arrows to show the logical connection between them, Flowcharts will flow from top to bottom, All flowcharts start with a Start Box and end with a Terminal Box,

33. Examples of Flowcharts for Algorithms Example 1: Calculate the sum of two integers and display the average. Algorithm: Step 1: Input num1, Step 2: Read num2, Step 3: Calcuate the sum, sum = num1 + num2 Step 4: Calculate average, ave = sum/2 Step 5: Print sum, ave

34. Flowchart: start INPUT NUM1 INPUT NUM2 SUM=NUM1+NUM2 AVE=SUM/2 PRINT SUM, AVE END INPUT NUM1, NUM2 SUM=NUM1+NUM2 AVE = SUM/2 PRINT SUM, AVE END

35. Determine and Output Whether Number N is Even or Odd Algorithm: Step 1: Read number N, Step 2: Set remainder as N modulo 2, Step 3: If remainder is equal to 0 then number N is even, else number N is odd, Step 4: Print output.

36. Determine Whether a Temperature is Below or Above the Freezing Point Algorithm: Step 1: Input temperature, Step 2: If it is less than 32, then print "below freezing point", otherwise print "above freezing point"

37. Determine Whether A Student Passed the Exam or Not: Algorithm: Step 1: Input grades of 4 courses M1, M2, M3 and M4, Step 2: Calculate the average grade with formula "Grade=(M1+M2+M3+M4)/4" Step 3: If the average grade is less than 60, print "FAIL", else print "PASS".

38. Your Turn Determine if a Number is positive or negative. Create the algorithm Draw the flowchart