DSA Lesson 2 - Algorithm and Flowcharting.pdf
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The document provides an introduction to algorithms and flowcharting, explaining what an algorithm is, its characteristics, and the steps for developing one. It also defines flowcharts, their purpose, and standard symbols used in flowcharting, including various examples of flowcharts for different programming tasks. Additionally, it includes practice tests for creating flowcharts based on specific scenarios.
DSA Lesson 2 - Algorithm and Flowcharting.pdf
- 1. ALGORITHM AND FLOWCHARTING Lesson 2 – Data Structures and Algorithm MR. ROWELL L. MARQUINA IT Instructor, PUP Biñan
- 3. What is an Algorithm? An algorithm refers to a series of well-defined instructions on how to accomplish a task or solve a specific problem. IMAGE SOURCE: https://imgbin.com/png/uxvDNRys/computer-programming-computer-icons-technology-algorithm-png https://www.flaticon.com/free-icon/coding_1085774 ▪ Giving directions on how to get to somebody’s house is an algorithm. ▪ The steps on how to change a light bulb is an algorithm. ▪ The steps to compute the for average is also an algorithm.
- 4. STEPS IN DEVELOPING AN ALGORITHM: 1. In creating an algorithm, it is very important to determine the exact goal or expected product first. The goal or expected product of the algorithm is called OUTPUT. 2. After determining the output, the next step is to identify the necessary materials or elements needed to accomplish the task. The elements needed for the program is called INPUT. 3. If the input and output are already identified, it is time to list the steps needed to accomplish the task. The steps needed to accomplish the task is referred to as the PROCESS.
- 5. CHARACTERISTICS OF AN ALGORITHM: An algorithm should possess the following characteristics: ▪ It should have well-defined input and output. ▪ The steps should be stated clearly and unambiguously. ▪ It should have an exact start and end. ▪ It should be simple but precise. ▪ It should be practical.
- 7. What is a Flowchart? A flowchart is a diagram that illustrates a process, system or computer algorithm. IMAGE SOURCE: https://www.frevvo.com/blog/wp-content/uploads/2021/10/image5-2.png Flowcharts are widely used in multiple fields for the purpose of: ▪ documentation ▪ planning ▪ analysis ▪ presentation
- 8. Flowchart Symbols The American National Standards Institute (ANSI) set standards for flowcharts and their symbols in the 1960s. IMAGE SOURCES: https://upload.wikimedia.org/wikipedia/commons/thumb/9/93/ANSI_logo.svg/1200px-ANSI_logo.svg.png https://1000logos.net/wp-content/uploads/2020/09/ISO-Logo.png In 1970 the International Organization for Standardization (ISO) adopted the ANSI symbols as the international standard for developing flowcharts.
- 10. Flowchart Symbols NAME OF SYMBOL SYMBOL FUNCTION Terminal Symbol Indicates the beginning and end of the flowchart. Flowline Symbol Its shows the process’ direction or the next steps in the process. Process Symbol It shows the process or operations to be carried out by the program Decision Symbol It shows the step that contains a control mechanism or decision. Input/Output Symbol It indicates the process of getting data from the user or displaying data on screen.
- 11. SAMPLE FLOWCHART 1: DETERMINING USER’S AGE Create a flowchart for a program that will require the user to input their year of birth. Using the user’s year of birth, the program will compute for the user’s age and display its result on the computer screen.
- 12. START birthyear, age display “Enter Year of Birth:” input birthyear age = 2023 - birthyear display age END The program is initiated. The variables birthyear and age were introduced to the program. The program displays the instruction “Enter Year of Birth: ” on the screen. The program get an input from the user and store its value in the variable birthyear. The program computes for the value of age using the formula age = 2023 - birthyear. The program displays the value of age on the screen. The program is terminated.
- 13. SAMPLE FLOWCHART 2: CONVERTING FROM KILOGRAM TO POUND Create a flowchart for a program that will require the user to input a value in kilogram (kg). The program will convert the inputted value into pounds (lbs.) and display its results on the screen.
- 14. START kilo, pound display “Enter Weight in Kilogram:” input kilo pound = kilo * 2.2 display pound END The program is initiated. The variables kilo and pound were introduced to the program. The program displays the instruction “Enter Weight in Kilogram: ” on the screen. The program get an input from the user and store its value in the variable kilogram. The program computes for the value of pound using the formula pound = kilo * 2.2. The program displays the value of pound on the screen. The program is terminated.
- 15. SAMPLE FLOWCHART 3: COMPUTING FOR AREA: Create a flowchart for a program that will require the user to input the length and width of a rectangle. The program will compute for the area of the rectangle using the inputted length and with and display its results on the screen.
- 16. START length, width, area display “Enter Length:” input length The program is initiated. The variables length, width, and area were introduced to the program. The program displays the instruction “Enter Length: ” on the screen. The program get an input from the user and store its value in the variable length. The program displays the instruction “Enter Width: ” on the screen. The program get an input from the user and store its value in the variable width. The program will be continued on the next slide. display “Enter Width:” input width A
- 17. area = length * width display area The program is continued. The program computes for the value of area using the formula area = length*width. The program displays the value of area on the screen. The program is terminated. A END
- 18. SAMPLE FLOWCHART 4: PLAYING WITH NUMBERS Create a flowchart for a program that will require the user to input four numbers. Using the inputs, the program will compute for: ▪ the sum of 1st and 2nd number, ▪ the product of the 3rd and 4th number ▪ the square of the 2nd number
- 19. START num1, num2, num3, num4, sum, product, square display “Enter the First Number: ” input num1 The program is initiated. The variables num1, num2, num3, num4, sum, product, and square were introduced to the program. The program displays the instruction “Enter the First Number: ” on the screen. The program get an input from the user and store its value in the variable num1. The program displays the instruction “Enter the Second Number: ” on the screen. The program get an input from the user and store its value in the variable num2. The program will be continued on the next slide. display “Enter the Second Number: ” input num2 A
- 20. display “Enter the Third Number: ” input num3 The program is continued. The program displays the instruction “Enter the Third Number: ” on the screen. The program get an input from the user and store its value in the variable num3. The program displays the instruction “Enter the Fourth Number: ” on the screen. The program get an input from the user and store its value in the variable num4. The program will be continued on the next slide. display “Enter the Fourth Number: ” input num4 B A sum = num1 + num2 The program computes for the value of sum using the formula sum = a + b.
- 21. display sum The program is continued. The program is terminated. display square B product = num3 * num4 The program computes for the value of product using the formula product = num3*num4. square = num2 * num2 display product END The program computes for the value of square using the formula square = num2 * num2. The program displays the value of sum on the screen. The program displays the value of product on the screen. The program displays the value of square on the screen.
- 22. SAMPLE FLOWCHART 5: PLAYING WITH NUMBERS Create a flowchart for a program that will require the user to input four numbers. Using the inputs, the program will compute for: ▪ the cube of the 1st number, ▪ the half of the 2nd number, ▪ the 20% of the 3rd number, ▪ The product of multiplying the 4th number by 100
- 23. START num1, num2, num3, num4, cube, half, twentyp, times100 display “Enter the First Number: ” input num1 The program is initiated. The variables num1, num2, num3, num4, cube, half, twentyp, and times100 were introduced to the program. The program displays the instruction “Enter the First Number: ” on the screen. The program get an input from the user and store its value in the variable num1. The program displays the instruction “Enter the Second Number: ” on the screen. The program get an input from the user and store its value in the variable num2. The program will be continued on the next slide. display “Enter the Second Number: ” input num2 A
- 24. display “Enter the Third Number: ” input num3 The program is continued. The program displays the instruction “Enter the Third Number: ” on the screen. The program get an input from the user and store its value in the variable num3. The program displays the instruction “Enter the Fourth Number: ” on the screen. The program get an input from the user and store its value in the variable num4. The program will be continued on the next slide. display “Enter the Fourth Number: ” input num4 B A cube = num1 * num1 * num1 The program computes for the value of cube using the formula cube = num1 * num1 * num1.
- 25. The program is continued. The program is terminated. B half = num2 / 2 The program computes for the value of half using the formula half = num2 / 2. twentyp = num3 * 0.20 END The program computes for the value of twentyp using the formula twentyp = num3 * 0.20. The program displays the value of cube on the screen. The program displays the value of half on the screen. The program displays the value of twentyp on the screen. times100 = num4 * 100 display cube display half display twentyp display times100 The program computes for the value of times100 using the formula times100 = num4 * 100. The program displays the value of times100 on the screen.
- 26. PRACTICE TEST 1: DOLLAR TO PESO CONVERSION Create a flowchart for a program that will require the user to input the amount in US Dollars. Using the inputted amount, the program will convert it to its Philippine Peso value and display the answer on the screen. Note: 1 US Dollar = Php 56.78
- 27. PRACTICE TEST 2: COMPUTING FOR AVERAGE Create a flowchart for a program that will require the user to input their grades in Mathematics, English, and Science. The program will compute for the average of the three grades and display its result on the computer screen.
- 28. PRACTICE TEST 3: PLAYING WITH NUMBERS Create a flowchart for a program that will require the user to input four numbers. Using the inputs, the program will perform the following: ▪ display the 1st number, ▪ get the product of 1st and 3rd number, ▪ get the product of multiplying the 2nd number by the sum of the 3rd and 4th number, ▪ the average of the four numbers increased by 5.
- 29. ALGORITHM AND FLOWCHARTING MR. ROWELL L. MARQUINA Professional Lecturer, Polytechnic University of the Philippines Email Address: [email protected] [email protected] [email protected]