L8:Flowcharting a program

1. ECE 2560 L8:Flowcharting a program Department of Electrical and Computer Engineering The Ohio State University ECE 3561 - Lecture 1

2. Flowcharting • Where does flowcharting come in? • Flowcharting symbols and examples • Flowcharting a program ECE 3561 - Lecture 1

3. What is flowcharting • Flowcharting is a method of documenting an algorithm or method for performing a sequence of actions. • Could be something that is not intended for a computer program. • Provides a graphical view of the process or method. • For assembler language can even indicate register and memory usage ECE 3561 - Lecture 1

4. Flowcharting symbols • Straight action (or code sequence) • Enclosed in a box – sequence of code goes in the box. • Example – exchange 2 items • A - -> Temp • B - -> A • Temp - -> B ECE 3561 - Lecture 1

5. Flowcharting symbols • Decision structure • Example • dec I • jge yes • Code for false branch • jmp after • yes Code for true branch • after code that follows structure ECE 3561 - Lecture 1

6. Flowcharting loops • A for loop • For I = 1 to 10 Loop • code in loop • End loop; ECE 3561 - Lecture 1

7. Flowchart for a problem • We considered multiply routine (note: different register numbers used here) • Note symbol for subroutine and enter/return ECE 3561 - Lecture 1

8. Other flowchart symbols • Have seem actions, decision, subprocess, enter/return • A couple of others that are often used ECE 3561 - Lecture 1

9. Flowchart hierarcy • Flowchart can be written such that what is in the action (process) box is a high level statement. • The high level statement can be a program in and of itself • OR • A flowchart can be done indicating assembler instructions and which registers are used. ECE 3561 - Lecture 1