1. Problem , Problem Solving, Algorithm & Flow Charts –Part 1
Week 10
Problem , Problem Solving, Algorithm & Flow Charts –Part 1
Presented By Mohamed El Saied Course:101 CS
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2. Objectives of the Session
Defining Problem
Defining Problem Solving
Need for Problem Solving
Problem Solving Strategy
Define-Algorithms- Rules of Algorithms
Examples of Algorithms
Define-Flowcharts-Rules of Flowchart
Examples of Flowcharts
Model Exercises
Take Away Tutorials
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3. Problem and Problem Solving
Definitions
The state of feeling difficulty in completing any task is called problem
The process of working through details of a problem to reach a solution. Problem solving may include mathematical or systematic operations and can be a gauge of an individual's critical thinking skills.
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4. Need for Problem Solving
A computer is a tool that can be used to implement a plan for solving a problem.
A computer program is a set of instructions for a computer. These instructions describe the steps that the computer must follow to implement a plan.
An algorithm is a plan for solving a problem.
A person must design an algorithm.
A person must translate an algorithm into a computer program.
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5. ALGORITHMS AND FLOWCHARTS
Step by step method to solve a problem is algorithm
Flow Chart
Diagrammatic representation of algorithm
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6. Divide and conquer strategy
A divide and conquer algorithm works by recursively breaking down a problem into two or more sub-problems of the same (or related) type, until solved
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7. 101CS Manesh T

8. Steps in development of Algorithms
Define Problem
Adopt Problem solving Method
Specify of Algorithm
Design an Algorithm
Check correctness of Algorithm
Analysis of Algorithm
Implementation of Algorithm
Test Algorithm
Documentation Preparation
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9. Qualities of a good algorithm
Inputs and outputs should be defined precisely.
Each steps in algorithm should be clear and unambiguous.
Algorithm should be most effective among many different ways to solve a problem.
An algorithm shouldn't have computer code. Instead, the algorithm should be written in such a way that, it can be used in similar programming languages.
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10. Algorithm Problem: How to brush your teeth Real life Example
Step 1: Start
Step 2: Wake up
Step 3: Wash mouth
Step 4: Wash brush, apply toothpaste
Step 5: Brush your teeth
Step 6. Wash mouth and brush
Step 7: Put brush back to holder
Step 8: Stop
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11. Problem: Add two numbers
Algorithm Step 1: Start Step 2: Read A, B Step 3: C=A+B Step 4: Print C Step 5: Stop
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12. Algorithm Problem: Subtract 2 numbers Problem: Multiply 2 numbers
Step 1: Start Step 2: Read A, B Step 3: C=A*B Step 4: Print C Step 5: Stop
Step 1: Start Step 2: Read A, B Step 3: C=A-B Step 4: Print C Step 5: Stop
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13. Algorithm Problem: Average of 3 numbers
Step 1: Start Step 2: Read A, B, C Step 3: Avg=(A+B+C)/3 Step 4: Print Avg Step 5: Stop
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14. Algorithm Problem: Find your Age
Step 1: Start Step 2: Read Byear Step 3: Age=2015-Byear Step 4: Print Age Step 5: Stop
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15. Algorithm Problem: Area of Circle
Step 1: Start
Step 2: Read Radius
Step 3: Area=3.14*Radius *Radius
Step 4: Print Area
Step 5: Stop
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16. Algorithm Problem: Find even or odd
Step 1: Start Step 2: Read N Step 3: Is (N%2=0) then Print “Even” else Print “Odd” Step 4: Stop
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17. Algorithm Problem: Find +ve or -ve
Step 1: Start Step 2: Read Number Step 3: Is (N>0) then Print “+ve number” else Print “-ve Number” Step 4: Stop
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18. Algorithm Problem: Find Pass or Fail
Detailed Algorithm
Step 1: Start
Step 2: Read Mark
Step 3: Is (Mark>=60) then
Print “PASS”
else
Print “Fail”
Step 4: Stop
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19. The Flowchart A Flowchart is another algorithm but graphical.
shows logic solution
emphasizes individual steps and their interconnections
A flowchart must have a start and stop
A steps in a flowchart must connect.
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20. Flowchart Symbols
General Used Symbols
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21. Flow Chart: Add Two Numbers
Algorithm
Start
Flowchart
Read A, B
C=A+B
Print C
Stop
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22. DECISION STRUCTURES The expression A>B is a logical expression
it describes a condition we want to test
if A>B is true (if A is greater than B) we take the action on left
print the value of A
if A>B is false (if A is not greater than B) we take the action on right
print the value of B
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23. DECISION STRUCTURES is
A>B Y N
Print A
Print B
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24. Flow Chart: Find Even or Odd
Start
Read N Is
N%2=0 Y N
Print “Odd”
Print “Even”
Stop
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25. Flow Chart: Find Largest of two numbers
Start
Read A, B Is
A>B Y N
Print “B is large”
Print “A is large”
Stop
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26. Problem: Write Algorithm and Flowchart to find solution of Quadratic equation
START
Read
a, b, c
d  sqrt(b x b – 4 x a x c)
STOP
x1 (–b + d) / (2 x a)
X2  (–b – d) / (2 x a)
Algorithm:
Step 1: Start
Step 2: Read a, b, c
Step 3: d  sqrt ( )
Step 4: x1  (–b + d) / (2 x a)
Step 5: x2  (–b – d) / (2 x a)
Step 6: Print x1, x2
Step 7: Stop
Print X1, X2
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27. Assignment 1 Draw algorithm and flowchart
Find area of triangle (area=(1/2)*breadth*height)
Convert Celsius to Fahrenheit temperature
f = (1.8*c) + 32;
Find Area of Rectangle (area= b*h)
Find Volume of cylinder(V= 3.14*R*R*Height)
Find volume of sphere (4/3* 3.14*R*R*R)
Find biggest of three numbers.
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28. Instructions to students
Study definition well
Study different algorithms well
Study how to draw flowchart for specific problems.
Work-out various assignment problems
Approach me for any doubt clarifications
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