1. Chapter 3 (Tutorial)

2. IF & CASE flow chart

3. PROGRAM if IF (consumed <250) THEN cost = consumed * 5
PROGRAM POWER_CONSUMPTION
IMPLICIT NONE
INTEGER :: consumed
REAL :: cost
WRITE (*,*) 'Enter consumed power (kWh) = '
READ (*,*) consumed
IF (consumed <250) THEN
cost = consumed * 5
ELSEIF (consumed <500) THEN
cost = consumed * 10
ELSE
cost = consumed * 20
END IF
WRITE (*,*) 'Payment = RO ', cost/1000
END PROGRAM
PROGRAM if

4. PROGRAM case PROGRAM POWER_CONSUMPTION IMPLICIT NONE
INTEGER :: consumed
REAL :: cost
WRITE (*,*) 'Enter consumed power (kWh) = '
READ (*,*) consumed
SELECT CASE (consumed)
CASE (:249)
cost = consumed * 5
CASE (250:499)
cost = consumed * 10
CASE DEFAULT
cost = consumed * 20
END SELECT
WRITE (*,*) 'Payment = RO ', cost/1000
END PROGRAM
PROGRAM case

5. If (logical_expr) GO TO
333 No
Yes
Go To 333

6. If (logical_expr) GO TO
PROGRAM Password_Check
IMPLICIT NONE
CHARACTER (len = 8) :: password
333 WRITE (*,*) ‘ENTER PASSWORD’
write (*,*)
READ (*,*) password
If (password /= ‘fortran’) GO TO 333
WRITE (*,*) “ OK, Password correct.”
END PROGRAM

7. Integrate all in one

8. Integrate all in one PROGRAM Protected_Power IMPLICIT NONE
CHARACTER (len = 8) :: password
INTEGER :: consumed
REAL :: cost
333 WRITE (*,*) 'ENTER PASSWORD'
write (*,*)
READ (*,*) password
If (password /= 'fortran') GO TO 333
WRITE (*,*) 'Enter consumed power (kWh) = '
READ (*,*) consumed
SELECT CASE (consumed)
CASE (:249)
cost = consumed * 5
CASE (250:499)
cost = consumed * 10
CASE DEFAULT
cost = consumed * 20
END SELECT
WRITE (*,*) 'Payment = RO ', cost/1000
END PROGRAM

9. One more trick
Make a non-terminated program that is always waiting for consumed power to calculate cost.

10. One more trick PROGRAM nonTerm_Power IMPLICIT NONE
CHARACTER (len = 8) :: password
INTEGER :: consumed
REAL :: cost
333 WRITE (*,*) 'ENTER PASSWORD'
write (*,*)
READ (*,*) password
If (password /= 'fortran') GO TO 333
444 WRITE (*,*) 'Enter consumed power (kWh) = '
READ (*,*) consumed
SELECT CASE (consumed)
CASE (:249)
cost = consumed * 5
CASE (250:499)
cost = consumed * 10
CASE DEFAULT
cost = consumed * 20
END SELECT
WRITE (*,*) 'Payment = RO ', cost/1000
GO TO 444
END PROGRAM

11. Practical Exercise
Design a FORTRAN program for the following problem and run it on computer.
A student need to calculate the GPA of a semester that consists of six courses.
The user should enter course number, course credits and grade letter for each course.
The ouput should be the overall semester GPA and total number of credits earned.