Program Program is a collection of instructions that will perform some task.

Problem Solving Steps Analyse the problem. Identify the solution for the problem and divide it into small task. Algorithm has to be prepared. Based on the algorithm the program will be created. Then it has to be executed.

Program Development Cycle Methodologies Program planning method Waterfall method etc,.

Program planning method Specification Review Informal Design Test & Debug Coding Formal Design Maintaining

Specification review –collect the requirements –understand the requirements Informal Design –Identifies the major tasks –Identifies the subtasks Formal Design –It converts the informal design to some format that can be understand by others.

Coding –It converts the Design into Programs. –It translate these programs to machine language. Test & Debug –It use sample data to test whether it works properly. –It also eliminate the errors.

Maintaining –It Modifies the programs if necessary.

Waterfall method Feasibility Analysis Maintenance Testing Impl Design

Feasibility –It determines whether it is possible to create the project or not. –It also produce the plans and the estimates. Analysis –It get the requirements from the customer. –It analysis the requirements.

Design –It is the process of designing how the requirements to be implemented. Implementation –It converts the designs into code. –After coding it use language translators to compile the code.

Testing –Here the modules are integrated together. –Then the project is tested and find whether it meets the customer/user requirements. Maintenance –It make modifications based on the customer feedbacks.

Algorithm Algorithm is a finite sequence of instructions required for producing the desired result.

Characteristics The steps in the algorithm must be unambiguous. It should be written in sequence. Ensure that the algorithm will terminate. It should conclude after a finite number of steps.

Factors used to judge the algorithm Time Memory Accuracy Sequence etc,.

Representations Flowcharts Normal English Pseudo code etc,.

Example Addition of two numbers Step1: Start Step2: Read a, b Step3: Add the value of a with b and store the result in c. Step4: Display the value of c Step5: Stop

Flowcharts It is the pictorial representation of the algorithm.

Flowchart Symbols Terminal symbol –It is used to represent the start, end of the program logic. Input/Output –It is used for input or output. Process Symbol –It is used to represent the calculations, data movements, initialization operations etc,.

Decision Symbol –It is used to denote a decision to be made at that point Flow lines –It is used to connect the symbols Connectors –It is used to connect the flow lines.

Guidelines for preparing flowcharts It should be simple. Standard symbols should be used. The flow lines should not intersect each others. In case of complex flowcharts use the connectors symbols.

Only one flow line should enter the process symbol and only one flow line should come out from a process symbol. Only one flow line used with the terminal symbol. START STOP

Only one flow line should enter the decision symbol and two or three flowlines may leave from the decision symbol.

Benefits of Flowcharts Makes Logic Clear Communication Effective Analysis Useful in coding Useful in Testing etc,.

Limits of Flowcharts It is difficult to use flowcharts for large program Difficult to modify Cost etc,.

Pseudocode Pseudo means imitates and code means instruction. It is formal design tool. It is also called Program Design Language.

Keywords READ,GET PRINT,DISPLAY COMPUTE,CALCULATE

Guideline for writing Pseudocode Steps should be understandable Capitalize the keyword. Indent to show hierarchy. End multiple line structure etc,.

Example READ a,b C=a+b WRITE C stop

Example READ a,b IF a>b PRINT a is greater ELSE PRINT b is greater ENDIF stop

Advantage & Disadvantage It can be easily modified It can be understood easily Compare to flowchart it is difficult to understand the program logic.

Sequence control structure Flow chartPseudocode Process 1 Process 2 Process n Process 2 Process n Process 1 Design Structures

Sequence control structure The instructions are computed in sequence i.e. it performs instruction one after another. It uses top-down approach. Design Structures

Example START C=a+b Print c Read a,b STOP

SELECTION CONTROL STRUCTURE It is used for making decisions. It allows the program to make a choice from alternative paths. IF …THEN IF …THEN… ELSE CASE etc.,

IF…THEN PseudocodeFlow chart IF condition THEN process 1.. END IF. If condition NO YES Process 1

Example Start Read a If a>0 Print a is Positive Stop no yes

IF…THEN…ELSE PseudocodeFlowchart IF condition THEN process 1. ELSE process 2.. END IF. If condition YES NO Process 1Process 2

Example Start Read a,b If a>b Print a is Greater Print b is Greater Stop no yes

CASE structure PseudocodeFlow chart. CASE Type Case Type-1: Process 1 Case Type-2: Process 2. Case Type-n: Process n. END CASE Type 1 Type 2 Type 3 Process 1 Process 2 Process 3 no yes

start stop Read m1,m2,m3 Avg=(m1+m2+m3)/3 If Avg>=60 If Avg>=50 If Avg>=35 Fail Print First Class Print Second Class Print Third Class Example: Finding the Grade

Looping control structure It is used to execute some instructions several time based on some condition. WHILE loop Do…WHILE loop etc.,

WHILE Loop PseudocodeFlow chart. WHILE condition. Body of the loop. END WHILE Body of The loop condition no yes

Example Start Num=0 Num=Num+1 Print Num while Num<5 stop no yes

DO…WHILE Loop PseudocodeFlow chart DO. Body of the loop. WHILE condition. END WHILE Body of The loop condition no yes

Example Start Num=0 Num=Num+1 Print Num while Num<5 stop no yes

Example: Finding the area of a circle Algorithm Step1: Start Step2: Read the value of r Step3: Calculate area = 3.14*r*r Step4: Print area Step5: Stop

Pseudocode Set area READ the r COMPUTE area=3.14*r*r PRINT area stop

Flowchart START area=3.14*r*r Print area Read r STOP

Find the largest among three Numbers Algorithm Step1: Start Step2: Read the value of a, b, c Step3: IF (a>b) and (a>c) THEN print a is largest ELSE IF (b>c) THEN print b is largest ELSE print c is largest Step4: Stop

Pseudocode READ a, b, c IF (a>b) and (a>c) THEN WRITE a is largest ELSE IF (b>c) THEN WRITE b is largest ELSE WRITE c is largest ENDIF stop

Flowchart START Print b Is largest Read a,b,c stop If (a>b) and (a>c) If b>c Print a Is largest Print c Is largest no yes no

Finding roots of the Quadratic equation Step:1 Start Step:2 Enter the values of a,b,c Step:3 Find the value of D Using the Formula, D = b*b-4*a*c Step:4 If D is greater than or equal to zero find 2 roots root1  (-b+sqrt(D))/(2*a) root2  (-b-sqrt(D))/(2*a) Step:5 Print root1 & root2 Step:6 If D is less than zero, then print the roots are imaginary Step:7 Stop

Pseudocode Set root1,root2 READ the value of a, b, c Find D  b*b-4*a*c IF D>=0 THEN calculate root1=(-b+sqrt(D))/(2*a) root2=(-b-sqrt(D))/(2*a) ELSE Roots are imaginary END IF WRITE root1,root2 Stop

Flow chart Start Stop D=b*b-4*a*c Root1=[-b+sqrt(D)]/(2*a) Root2=[-b+sqrt(D)]/(2*a) Read a,b,c Print root1,root2 If D>=0 no yes Print roots are imaginary

Swapping two variables Algorithm Step1: Start Step2: Read the value of a, b Step3: c = a a = b b = c Step4: Print the value of a and b Step5: Stop

Pseudocode READ the value of a, b To swap use c = a a = b b = c WRITE a, b stop

Flowchart START c = a a = b b = c Print a, b Read a, b STOP

Swapping two variables without using another variable Algorithm Step1: Start Step2: Read the value of a, b Step3: a = a + b b = a - b a = a - b Step4: Print the value of a and b Step5: Stop

Pseudocode READ the value of a, b To swap use a = a + b b = a - b a = a - b WRITE a, b stop

Flowchart START a = a + b b = a - b a = a - b Print a, b Read a, b STOP

Finding the year is leap year or not Algorithm Step1: Start Step2: Read the value of year Step3: IF year % 4 ==0 THEN print It is a Leap year ELSE print It is not a Leap year Step4: Stop

Pseudocode READ year IF year % 4 ==0 THEN WRITE It is a Leap year ELSE WRITE It is not a Leap year ENDIF stop

Flowchart Start Read year year % 4 ==0 Print It is a Leap year Print It is not a Leap year Stop no yes

Finding the Factorial Algorithm Step1: Start Step2: Read the value of n and set i =1 Step3: While i <= n do fact =fact * i i = i + 1 else Goto step5 Step4: Goto step 3 Step5: print the value of fact Step6: Stop

Pseudocode READ the value of n and set i =1 WHILE (i <= n) do fact =fact * i i = i + 1 ENDWHILE Repeat the loop until condition fails WRITE fact stop

Flowchart Start Read n i = 1 fact=fact * i i=i+1 Print fact while i<=n stop no yes

Finding the Sum of the digits Algorithm Step1: Start Step2: Read the value of n and set i = 0, sum = 0 Step3: While n>0 do r=n%10 sum=sum + r n=n/10 else Goto step5 Step4: Goto step 3 Step5: print the value of sum Step6: Stop

Pseudocode READ the value of n and set i =0, sum=0 WHILE (n>0) do r=n%10 sum=sum + r n=n/10 ENDWHILE Repeat the loop until condition fails WRITE sum stop

Flowchart Start r = 0,sum=0 r=n%10 sum=sum + r n=n/10 Print sum while n>0 stop no yes Read n

Finding the Reverse of a Number Algorithm Step1: Start Step2: Read the value of n and set i = 0, sum = 0 Step3: While n>0 do r=n%10 sum=sum *10 + r n=n/10 else Goto step5 Step4: Goto step 3 Step5: print the value of sum Step6: Stop

Pseudocode READ the value of n and set i =0, sum=0 WHILE (n>0) do r=n%10 sum=sum *10 + r n=n/10 ENDWHILE Repeat the loop until condition fails WRITE sum stop

Flowchart Start r = 0,sum=0 r=n%10 sum=sum *10 + r n=n/10 Print sum while n>0 stop no yes Read n

Armstrong Number Example: =153

Finding an Armstrong Number Algorithm Step1: Start Step2: Read the value of n and set a = n, sum = 0 Step3: While n>0 do r=n%10 sum=sum + r*r*r n=n/10 else Goto step5 Step4: Goto step 3 Step5: If a = sum then Print Armstrong Number Else Print It is Not an Armstrong Number Endif Step6: Stop

Pseudocode READ the value of n and set a =n, sum=0 WHILE (n>0) do r=n%10 sum=sum + r*r*r n=n/10 ENDWHILE Repeat the loop until condition fails IF a=sum THEN WRITE Armstrong Number ELSE WRITE It is not an Armstrong Number ENDIF stop

Flowchart Start a = n,sum=0 r=n%10 sum=sum + r*r*r n=n/10 Print Armstrong No while n>0 stop no yes Read n if a=sum Print It is Not an Armstrong No

Fibonacci series Example: ….

Finding the Fibonacci series Algorithm Step1: Start Step2: Read the value of n and set f=0,f1=-1, f2=1 Step3: While (f<n) do f=f1+f2 f1=f2 f2=f Print f else Goto step5 Step4: Goto step 3 Step5: Stop

Pseudocode READ the value of n and set f=0,f1=-1, f2=1 WHILE (f<n) do f=f1+f2 f1=f2 f2=f WRITE f ENDWHILE Repeat the loop until condition fails stop

Flowchart Start f=0,f1= -1,f2=1 f=f1+f2 f1=f2 f2=f Print f while f<n stop no yes Read n

Conversion of Celsius to Fahrenheit Algorithm Step1: Start Step2: Read the value of Celsius Step3: Fahrenheit = (1.8* Celsius) + 32 Step4: Print Fahrenheit Step5: Stop

Pseudocode Set Fahrenheit READ the Celsius COMPUTE Fahrenheit = (1.8* Celsius) + 32 PRINT Fahrenheit stop

Flowchart START Fahrenheit = (1.8* Celsius) + 32 Print Fahrenheit Read Celsius STOP

Conversion of Fahrenheit to Celsius Algorithm Step1: Start Step2: Read the value of Fahrenheit Step3:Calculate Celsius =(Fahrenheit – 32)/1.8 Step4: Print Celsius Step5: Stop

Pseudocode Set Celsius READ the Fahrenheit COMPUTE Celsius =(Fahrenheit – 32)/1.8 PRINT Celsius stop

Flowchart START Celsius =(Fahrenheit – 32)/1.8 Print Celsius Read Fahrenheit STOP

Finding the sum of odd number between 1 to n Algorithm Step1: Start Step2: Read the value of n and set sum=0,i=1 Step3: While (i<=n) do sum=sum+i i=i+2 else Goto step5 Step4: Goto step 3 Step5: Print sum Step6: Stop

Pseudocode READ the value of n and set sum=0,i=1 WHILE (i<=n) do sum=sum+i i=i+2 ENDWHILE Repeat the loop until condition fails WRITE sum stop

Flowchart Start sum=0,i=1 sum=sum+i i=i+2 Print sum stop Read n While i<=n

Finding the sum of even number between 1 to n Algorithm Step1: Start Step2: Read the value of n and set sum=0,i=0 Step3: While (i<=n) do sum=sum+i i=i+2 else Goto step 5 Step4: Goto step 3 Step5: Print sum Step6: Stop

Pseudocode READ the value of n and set sum=0,i=0 WHILE (i<=n) do sum=sum+i i=i+2 ENDWHILE Repeat the loop until condition fails WRITE sum stop

Flowchart Start sum=0,i=0 sum=sum+i i=i+2 Print sum stop Read n While i<=n

Conversion of Binary number to Decimal Algorithm Step1: Start Step2: Read the value of n and set i = 0, sum = 0 Step3: While n>0 do r=n%10 sum=sum + r*pow(2,i) n=n/10 i=i+1 else Goto step5 Step4: Goto step 3 Step5: print the value of sum Step6: Stop

Pseudocode READ the value of n and set i =0, sum=0 WHILE (n>0) do r=n%10 sum=sum + r*pow(2,i) n=n/10 i=i+1 ENDWHILE Repeat the loop until condition fails WRITE sum stop

Flowchart Start sum=0,i=0 Print sum stop Read n While n>0 r=n%10 sum=sum + r*Pow(2,i) n=n/10 i=i+1