1. Basic problem solving
CSC 111

2. Learning Objectives In this lecture we will learn
Basic steps for designing computer program
Algorithm
Flow Chart
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3. Solving Problems Stages
Problem Definition
Define the main Problem
Problem Analysis
Determine the inputs, outputs, Arithmetic & logic operations
Design Solution
Identify the required step for computer to do
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4. Problem Definition
Write a Program to Print the Sum of two integer Numbers
Write a program to Print the Average of three integer numbers
Write a program to print the volume of a cube and the sum of it’s surfaces’ areas
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5. Problem Analysis
Write a Program to Print the Sum of two integer Numbers
Inputs :
First Number
Second Number
Operations :
Summation = first + second
Output :
The summation
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6. Problem Analysis
Write a program to Print the Average of three integer numbers
Inputs :
First Number
Second Number
Third Number
Operations :
Average = (first + second + third ) / 3
Output :
The Average
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7. Problem Analysis
Write a program to print the volume of a cube and the sum of it’s surfaces’ areas
Inputs :
Side Length
Operations :
Volume = side * side * side
Surface area = ( side * side ) * 6
Output :
The Volume
The surface area
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8. Solving Problems Stages
Problem Definition
Algorithm
Problem Analysis
Solution Design
Design a solution for the problem by writing an algorithm or drawing a flow chart
Flow Chart
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9. Basic steps for designing a solution
Read all the inputs
Calculate operations
Print the output
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10. Algorithms Write a Program to Print the Sum of two integer Numbers
Start the program
Read the first number and save in the variable ( N1 )
Read the second number and save in the variable ( N2 )
Sum the both numbers and save the result in the variable ( Sum )  Sum = N1 + N2
Print the variable ( Sum )
End the program
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11. Algorithms
Write a program to Print the Average of three integer numbers
Start the program
Read the first number and save in the variable ( num1 )
Read the second number and save in the variable ( num2 )
Read the third number and save in the variable ( num3 )
Sum the three numbers and save the result in the variable ( result )  result = num1 + num2 + num3
Divide the variable ( result ) by 3 and save the result in variable ( Average )  Average = result / 3
Print the variable ( Average )
End the program
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12. Algorithms
Write a program to print the volume of a cube and the sum of it’s surfaces’ areas
Start the program
Read the length of the side and save in variable ( Length )
Volume = Length * Length * Length
Surface = ( Length * Length ) * 6
Print the variable ( Volume )
Print the variable ( Surface )
End the program
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13. Flow Chart
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14. Flow chart’s Symbols Start/End End Start Read/Print Print n1 Read n1
Arithmetic Operations
N2 = n1+3
N2 = 5
Decision
n1 > 3
Loops
Connectors arrows
Connectors points
Comments
Java Programming: From Problem Analysis to Program Design, Third Edition
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15. Simple Sequential Flow Charts
start
End
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16. Write a Program to Print the Sum of two integer Numbers
start
Start the program
Read the first number and save in the variable ( N1 )
Read the second number and save in the variable ( N2 )
Sum the both numbers and save the result in the variable ( Sum )  Sum = N1 + N2
Print the variable ( Sum )
End the program
Read N1
Read N2
Sum = N1 + N2
Print Sum
End
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17. Computer Programming -1
Write a program to print the volume of a cube and the sum of it’s surfaces’ areas
start
Start the program
Read the length of the side and save in variable ( Length )
Volume = Length * Length * Length
Surface = ( Length * Length ) * 6
Print the variable ( Volume )
Print the variable ( Surface )
End the program
Read L
Volume = L * L * L
ٍSurface = ( L * L ) * 6
Print Volume
Print Surface
End
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18. Write a program to Print the Average of three integer numbers
start
Read num1
start
Read num2
Read num1,num2,num3
Read num3
result = num1+num2+num3
result = num1+num2+num3
Average = result/3
Average = result/3
Print Average
Print Average
End
End
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19. Write a program to Print the Average of three integer numbers
start
Read num1,num2,num3
Average = ( num1+num2+num3 ) / 3
Print Average
End
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20. Write a program to Print the Average of three integer numbers
start
start
result = num1+num2+num3
Read num3
Read num1
Read num1
Read num2
Read num2
result = num1+num2+num3
Read num3
Average = result/3
Average = result/3
Print Average
Print Average
End
End
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21. Write a program to Print the Average of three integer numbers
start
start
Read num1,
num2,num3
Read num1,
num2,num3
result = num1+num2+num3
Average = result/3
Average = result/3
result = num1+num2+num3
Print result
Print Average
Print result
End
End
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22. Summery
A problem-solving process for programming has five steps: analyze the problem, design an algorithm, implement the algorithm in a programming language, verify that the algorithm works, and maintain the program.
An algorithm is a step-by-step problem-solving process in which a solution is arrived at in a finite amount of time.
A flowchart is a type of diagram that represents an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting them with arrows.
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