BASIC PROBLEM SOLVING

CSC 111

2

Computer Programming -1

Learning Objectives

In this lecture we will learn

1. Basic steps for designing computer program

2. Algorithm

3. Flow Chart

Computer Programming -1

3

Solving Problems Stages

1. Problem Definition Define the main Problem

2. Problem Analysis Determine the inputs, outputs, Arithmetic &

logic operations

3. Design Solution Identify the required step for computer to do

Computer Programming -1

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

Computer Programming -1

5

Problem Analysis

Write a Program to Print the Sum of two integer Numbers

Inputs :First NumberSecond Number

Operations :Summation = first + second

Output :The summation

Computer Programming -1

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

Computer Programming -1

7

Problem Analysis

Write a program to print the volume of a cube and the sum of it’s surfaces’ areas

Inputs :1. Side Length

Operations : Volume = side * side * side Surface area = ( side * side ) * 6

Output :1. The Volume

2. The surface area

Computer Programming -1

8

Solving Problems Stages

Problem Definition

Problem Analysis

Solution DesignDesign a solution for the problem by writing an algorithm or drawing a flow chart

Algorithm

Flow Chart

Computer Programming -1

9

Basic steps for designing a solution

Read all the inputs

Calculate operations

Print the output

Computer Programming -1

10

Algorithms

Write a Program to Print the Sum of two integer Numbers

1. Start the program2. Read the first number and save in the variable ( N1 )3. Read the second number and save in the variable ( N2 )4. Sum the both numbers and save the result in the

variable ( Sum ) Sum = N1 + N2 5. Print the variable ( Sum ) 6. End the program

Computer Programming -1

11

Algorithms

Write a program to Print the Average of three integer numbers

1. Start the program2. Read the first number and save in the variable ( num1 )3. Read the second number and save in the variable ( num2 )4. Read the third number and save in the variable ( num3 )5. Sum the three numbers and save the result in the variable

( result ) result = num1 + num2 + num36. Divide the variable ( result ) by 3 and save the result in

variable ( Average ) Average = result / 3 7. Print the variable ( Average )8. End the program

Computer Programming -1

12

Algorithms

Write a program to print the volume of a cube and the sum of it’s surfaces’ areas

1.Start the program

2.Read the length of the side and save in variable ( Length )

3.Volume = Length * Length * Length

4.Surface = ( Length * Length ) * 6

5.Print the variable ( Volume )

6.Print the variable ( Surface )

7.End the program

13

Computer Programming -1

Flow Chart

Java Programming: From Problem Analysis to Program Design, Third Edition

14

Flow chart’s Symbols

Loops

Start/End

Read/Print

Arithmetic Operations

Decision

Connectors arrows

Connectors points

Comments

Start

Read n1

N2 = 5

End

Print n1

N2 = n1+3

n1 > 3

//my name

Computer Programming -1

15

Simple Sequential Flow Charts

start

End

Computer Programming -1 16

16

Write a Program to Print the Sum of two integer Numbers

1. Start the program2. Read the first number and save in

the variable ( N1 )3. Read the second number and save

in the variable ( N2 )4. Sum the both numbers and save

the result in the variable ( Sum ) Sum = N1 + N2

5. Print the variable ( Sum ) 6. End the program

start

Read N1

Read N2

Sum = N1 + N2

Print Sum

End

17

17

Computer Programming -1

Write a program to print the volume of a cube and the sum of it’s surfaces’ areas

1. Start the program2. Read the length of the side and

save in variable ( Length )3. Volume = Length * Length * Length4. Surface = ( Length * Length ) * 65. Print the variable ( Volume ) 6. Print the variable ( Surface )7. End the program

start

Read L

&ٍSurface = ( L * L ) * 6

Print Volume

End

Volume = L * L * L

Print Surface

Computer Programming -1 18

18

Write a program to Print the Average of three integer numbers

start

Read num1

Read num2

result = num1+num2+num3

Print Average

End

Read num3

Average = result/3

start

Read num1,num2,num3

result = num1+num2+num3

Print Average

End

Average = result/3

Computer Programming -1 19

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

Computer Programming -1 20

20

Write a program to Print the Average of three integer numbers

start

Read num1

Read num2

Print Average

End

Read num3

Average = result/3

result = num1+num2+num3

start

Read num3

Read num1

result = num1+num2+num3

Print Average

End

Read num2

Average = result/3

Computer Programming -1 21

21

Write a program to Print the Average of three integer numbers

start

Read num1,num2,num3

result = num1+num2+num3

Print result

End

Average = result/3

start

Read num1,num2,num3

Print result

End

Average = result/3

result = num1+num2+num3

Print Average

Computer Programming -1

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.