1. 情報基礎B　　 Lecture 7
Takeshi Tokuyama Tohoku University Graduate School of Information Sciences System Information Sciences Design and Analysis of Information Systems

2. COMPUTATION AND PROGRAMMING

3. Computation The world of {0, 1} AND operation OR operation
Boolean algebra
Logical operation
AND operation
0 × 0 = 0 × 1 = 1 × 0 = 0, 1 × 1 = 1
Series circuit
OR operation
0 + 0 = 0, = = 1, = 1
Parallel circuit
NOT operation
NOT(0) = 1, NOT(1) = 0
NOT

4. Computation AND operation 0 × 0 = 0 × 1 = 1 × 0 = 0, 1 × 1 = 1
Series circuit
Switching : relay, transistor, diode

5. Computation OR operation 0 + 0 = 0, 0 + 1 = 1 + 0 = 1, 1 + 1 = 1
Parallel circuit

6. Computation a NOT(a) NOT operation NOT(0) = 1, NOT(1) = 0
electromanget
NOT(a)

7. Example of Adder a b Circuit to calculate a + b (a, b = 0 or 1)
0 + 0 = 00
1 + 0 = 01
0 + 1 = 01
1 + 1 = 10
NOT
Upper Bit
Lower Bit

8. Computation Model AND, OR, NOT Logical operation
Addition, subtraction, multiplication, division, comparison IF
Programming model (decision tree model)
Load data from storage
Store data to storage

9. Program and Decision Tree
IF(B2>=90, “A”,
IF(B2>=80, “B”,
IF(B2>=70, “C”,
IF(B2>=60, “D”, “F”)))) B2
True
False A
True
False B
True
False C
True
False D F
Computation proceeds through the tree

10. Loop SUM(A2:A100) Decision tree becomes deep Loop structure
Loop management
When to stop?
In Excel…
By setting range A2:A100
Read a cell in column A
Adder
Temporal
Result

11. Loop Example: SUM(A2:A100) i=2 i = i + 1 Read A(i) TRUE Adder i<100
Temporal
Result
i = i + 1
TRUE
i<100
FALSE
Output
Temporal Result

12. Programming Think about an algorithm
e.g. Grading procedure
Show a flowchart with decision tree and loop structure
Write the algorithm in programming language
Small vocabulary, easy

13. Programming Make an operation which a computer work on
Algorithm designing
Logical work
Coding
Learning a programming language
Read programs
Make some change on programs
Debug(Error correction)

14. Programming hints Learning programming language Follow examples
Practice makes perfect
Follow examples
This is a pen > This is a dog
Follow good examples
Learn from the mistakes
This is a apple ??
I is a man ??
System will tell you mistakes
Guess what is wrong: logical mind and imagination

15. Exercise
Write a flowchart of program that acts same as COUNTIF(B2:B21, “A”) without using COUNTIF