1. ICS 101 Lab 3 Hossain Arif ICS Dept
Logical Operations
ICS 101 Lab 3
Hossain Arif
ICS Dept

2. Objective What are Logical Operations What are Relational Operations
What are Logical Expressions
Logical Expressions Evaluation
Examples
Exercises

3. Arithmetic Operations(1)
Arithmetic operators
Precedence
Math Notation
Example
Operation
FORTRAN Operator 1 XY
X ** Y
Exponentiation ** 2
X x Y
X * Y
Multiplication *
X ÷ Y
X / Y
Division / 3
X + Y
Addition +
X - Y
Subtraction -
Parentheses () have the highest precedence

4. Arithmetic Operations(2)
Two restrictions
No two operators must appear consecutively
2 * -3 should be written as 2 * (-3)
Exponential operator must not be used to raise a negative number to a real exponent
(-2.0) ** 1.5 and (-3) ** 2.3 are not allowed in FORTRAN

5. Arithmetic Operations(3)
Integer operations
An operator between two integer operands
Produces integer results
In division, the fraction part is truncated
Examples:
50 – 23
3 ** 2
5 * 7
8 / 3
9 / 10
17 / 6 * 6

6. Arithmetic Operations(4)
Real operations
An operator between two real operands
Produces real results
Examples:
50.0 – 23.0
3.0 ** 2.0
5.0 * 7.0
9. / 10.
9.3 / 3.2

7. Arithmetic Operations(5)
Mixed-mode operations
An operator between an integer operand and a real operand
Produces real results
Examples:
50 – 23.0
3.0 ** 2 , 3 ** 2.0
65.7 / 7
8.0 / 2
9 / 10.

8. Logical Operations(1) Logical Operations Logical Operators: .NOT. P
Evaluate to either .TRUE. or .FALSE.
Logical Operators:
.NOT. P
P .OR. Q
P .AND. Q Q P
.TRUE.
.FALSE.
.NOT. operator has the highest precedence (1) followed by .AND. (2) then .OR. (3)

9. Logical Operations(2) Relational operators Example Math Operator
X .EQ. Y =
.EQ.
N .NE. 8 ≠
.NE.
P .GT. 7.3
>
.GT.
SM .GE. TOT ≤
.GE.
A+B .LT. A*2.0
<
.LT.
NUM .LE. C ≥
.LE.
Relational operators have lower precedence than arithmetic operators and higher precedence than logical operators

10. Logical Operations(3) Logical expressions
Evaluated to .TRUE. or .FALSE.
May contain different types of variables and operators
Examples:
.NOT. FLAG .AND. X * Y .GT. Z .OR. X + Y .GT. Z
Where X has a value of 3.0, Y has a value of 5.0, Z has a value of 10.0, and FLAG is logical variable with .FALSE. value
K / L * L .EQ. K
Where K and L are integers

11. Examples .NOT. FLAG .AND. X * Y .GT. Z .OR. X + Y .GT. Z
.NOT. FLAG .AND GT OR GT. 10.0
.NOT. FLAG .AND. .TRUE. .OR. .FALSE.
.TRUE. .AND. .TRUE. .OR. .FALSE.
.TRUE. .OR. .FALSE.
.TRUE.

12. Precedence Summary Arithmetic Operators (1) Relational Operators (2)
Exponentiation (I)
Multiplication / Division (II)
Addition / Subtraction (III)
Relational Operators (2)
Logical Operators (3)
.NOT. (#)
.AND. (##)
.OR. (###)
To change Precedence (Priority) use Parentheses

13. Exercise Find the value for each of the following expressions
X= 3.0, Y = 5.0, Z = 10.0, FLAG = .FALSE.
.NOT. FLAG .OR. FLAG
X .GT. Y – Z / 2.0
X * Z .EQ OR. FLAG .AND. .NOT. Z .EQ. 5.0
.NOT. FLAG .AND. FLAG