SPL 2 | Algorithms, Pseudo-code, and Flowchart
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The document discusses structured programming languages and the compilation process. It provides algorithms, pseudocode, and flowcharts for finding the average of n numbers as an example. It then explains the four stages of compiling a C program: preprocessing, compilation, assembly, and linking. Preprocessing handles includes, defines, and macros. Compilation generates assembly code. Assembly produces object code. Linking combines object files and libraries into a single executable file.
SPL 2 | Algorithms, Pseudo-code, and Flowchart
- 1. Structured Programming Language ALGORITHM, PSEUDO CODE, FLOW CHART, COMPILATION PROCESS Mohammad Imam Hossain Lecturer, CSE, UIU
- 2. Algorithm • Complete step by step representation of the solution of the problem, represented in English like language. Pseudo Code • More formal representation than the algorithm • Very close to actual programming language Flow chart • Uses many graphical symbols to represent the steps of the solution of the problem. Program • A set of instructions • Written in a particular sequence in a computer-related language
- 3. Problem:Write a program to find the average of n numbers. Algorithm: 1. Read the value of n 2. Read n numbers 3. Add these n numbers 4. Divide the addition result by n to get the average 5. Print the average Pseudo Code: 1. Start 2. Read n 3. sum 0 4. for i 1 to n do 5. read i-th number 6. sum sum + i-th number 7. end for 8. average sum/n 9. print average 10. stop
- 4. Flow Chart • Graphical Symbols Start, Stop Read, Print Processing statements Conditional check Direction of flow Connectors
- 5. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 6. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 7. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 8. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 9. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 10. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 yes no
- 11. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 yes no
- 12. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 yes no
- 13. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 yes no
- 14. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 yes no
- 15. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 yes no
- 16. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 yes no
- 17. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 sum=30+30=60, i=4 yes no
- 18. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 sum=30+30=60, i=4 yes no
- 19. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 sum=30+30=60, i=4 average=60/3=20 yes no
- 20. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 sum=30+30=60, i=4 average=60/3=20 yes no
- 21. Problem:Write a program to find the average of n numbers. Flow Chart >> start Read n sum 0 i 1 i<= n ? Read numberi sum sum + numberi ii+1 average sum/n Print average stop n=3 and the numbers are: 10,20,30 sum=0+10=10, i=2 sum=10+20=30, i=3 sum=30+30=60, i=4 average=60/3=20 yes no
- 22. Practice problems: 1. Draw flow chart to decide whether a number is even or odd. 2. Draw flow chart to find out the sum of the following series: a) 1+3+5+… … + 99 b) 1+ 1 3 + 1 5 + … … + 1 27 c) 1+1+2+3+5+8+13+… … + upto 100th terms (Fibonacci series) 3. Draw flow chart to find out the factorial of n, 1*2*3*… … *n 4. Draw flow chart to find out the maximum of 3 numbers. 5. Draw flow chart to check whether a number is prime or not. 6. Draw flow chart to find out the gcd of 2 numbers.
- 23. GCD Problem: 15 ) 21 ( 1 15 --------------- 6 ) 15 ( 2 12 -------------- 3 ) 6 ( 2 6 ------------ 0
- 24. GCD Problem: 15 ) 21 ( 1 15 --------------- 6 ) 15 ( 2 12 -------------- 3 ) 6 ( 2 6 ------------ 0 a b check
- 25. GCD Problem: 15 ) 21 ( 1 15 --------------- 6 ) 15 ( 2 12 -------------- 3 ) 6 ( 2 6 ------------ 0 a b check
- 26. GCD Problem: 15 ) 21 ( 1 15 --------------- 6 ) 15 ( 2 12 -------------- 3 ) 6 ( 2 6 ------------ 0 a b check
- 27. GCD Problem: 15 ) 21 ( 1 15 --------------- 6 ) 15 ( 2 12 -------------- 3 ) 6 ( 2 6 ------------ 0 a b check Start input a , b check b % a check=0 ? ba a check print a stop No Yes check b % a
- 28. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c C Preprocessor
- 29. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i C Preprocessor
- 30. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i C Preprocessor C Compiler 2. Compilation is the second pass. It takes the output of the preprocessor and the source code and generates assembler source code.
- 31. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i Assembly code hello.s C Preprocessor C Compiler 2. Compilation is the second pass. It takes the output of the preprocessor and the source code and generates assembler source code.
- 32. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i Assembly code hello.s C Preprocessor C Compiler Assembler 2. Compilation is the second pass. It takes the output of the preprocessor and the source code and generates assembler source code. 3. Assembly is the third stage that takes the assembly source code and produces an assembly listing with offsets.The assembler output is stored in an object file.
- 33. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i Object code hello.o Assembly code hello.s C Preprocessor C Compiler Assembler 2. Compilation is the second pass. It takes the output of the preprocessor and the source code and generates assembler source code. 3. Assembly is the third stage that takes the assembly source code and produces an assembly listing with offsets.The assembler output is stored in an object file.
- 34. C Programs Building Process: C program building process involves four stages. At the end there should be a single executable file. 1. Preprocessing is the first pass of any C compilation. It processes include-files, define, conditional compilation instructions and macros. Source Code hello.c PreprocessedCode hello.i Executable code hello.exe Object code hello.o Assembly code hello.s C Preprocessor C Compiler Assembler Linker 2. Compilation is the second pass. It takes the output of the preprocessor and the source code and generates assembler source code. 3. Assembly is the third stage that takes the assembly source code and produces an assembly listing with offsets.The assembler output is stored in an object file. 4. Linking is the final stage that takes one or more object files or libraries as input and combines them to produce a single (executable) file. Library Files Other Object files Relocation object code information
- 35. Compiling using command prompt: 1. Write your code into a text editor and name the file with .c extention. 2. Add your gcc compiler’s bin directory path into windows environment variables path variable. 3. Open windows command prompt and write the following command gcc –c “path of your .c file with file name” This command will generate the object file with .o extension let, object_file_name.o 4.Then give the following command gcc –o exe_file_name object_file_name.o