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CHAPTER 4
CONDITIONAL STATEMENTS
Conditional statements, in particular the block IF, are the
workhorses of the Fortran language. They are executable
statements, used to conditionally execute:
The conditional execution of a block is accomplished with
the block IF. The conditional execution of a statement is
accomplished with the logical IF. The conditional transfer of
control is accomplished with the arithmetic IF.
The block IF is by far the most commonly used IF statement.
The logical IF has limited application, although it remains in
use. The arithmetic IF is a remnant of older versions of the
language, and it has been categorized as obsolescent by the
Fortran 90 standard (see Section 1.4). Accordingly, its use is
discouraged in the development of new programs.
A block is a set of zero or more executable statements that
is treated as a unit. A null block has zero statements.
Execution of a null block has no effect.
A block IF construct consists of one or more blocks
separated by the partial statements IF (exp) THEN, ELSE IF
(exp) THEN, ELSE, and END IF. The word exp enclosed in
parentheses stands for a logical expression.
A block IF construct always begins with the partial
statement IF (exp) THEN and ends with the partial statement
END IF. A block forming part of a block IF construct is
conditionally executed based on the satisfaction of the logical
expression exp contained in the partial statement statement IF
(exp) THEN or ELSEIF (exp) THEN immediately preceding it.
Example of Block IF Construct Sequence
IF (exp1) THEN ... !
Block 1 ELSE IF (exp2) THEN ... !
Block 2 ELSE IF (exp3) THEN ... ! Block 3 ELSE IF (exp4)
THEN
Block 4 ELSE ... ! Block 5 ENDIF
4.1 LOGICAL EXPRESSIONS
A logical expression is one that can take a value of true
(.TRUE.) or false (.FALSE.). Logical expressions link two
variables with relational and/or logical operators. Table 4.1
shows a list of relational operators. Table 4.2 shows a list of
logical operators.
TABLE 4.1 RELATIONAL OPERATORS
| Operator
|
Meaning
|
| x.GT.y
x.GE.y
x.LT.y
x.LE.y
m.EQ.n
m.NE.n |
x greater than y
x greater than or equal to y
x less than y
x less than or equal to y
m equal to n
m not equal to n |
Note: Relational operators are shown in upper case, enclosed
by delimiting periods.
TABLE 4.2 LOGICAL OPERATORS
|
Operator |
Meaning |
| a.AND.b
a.OR.b
a.NEQV.b
a.EQV.b
NOT.b
|
The expression is true if both a and b are true;
the expression is false otherwise.
The expression is
true if either a or b are true, or both are true;
the expression is false otherwise.
The expression
is true if a and b are not equivalent;
the expression is false if a and b are the same.
The expression is true if a and b are the same;
the expression is false if a and b are not equivalent.
The expression is true if b is false;
the expression is false if b is true. |
Note: Logical operators are shown in upper case, enclosed by
delimiting periods.
A relational expression is a special type of logical
expression consisting of two arithmetic expressions connected
by a relational operator, for example:
X.GT.Y
where X and Y are arithmetic expressions and GT is a
relational operator. The delimiting periods are required. During
execution, the relational expression is evaluated. If X is
greater than Y, the relational expression is assigned the value
.TRUE.; otherwise, it is .FALSE.
Complex variables can be related only with the .EQ. and .NE.
relational operators (see Table 4.1). Furthermore, two complex
values are equal only if their corresponding real and
imaginary parts are equal.
The following are additional examples of relational
expressions:
Y.GE.Z
A+B.LT.C*D X+Y.LE.P/Q
JTIME.EQ.KTIME
APPLE.NE.ORANGE
All variables included in these examples are of numeric data
type (integer, real, complex, or double precision).
A logical expression can contain any combination of
relational and/or logical operators (including the case of no
operator), as shown in the following examples:
A
A.AND.B
C.GT.D.AND.X.LE.Y
A and B are logical expressions; C, D, X, and Y are
arithmetic expressions. The delimiting periods are required. During
execution, the logical expression is evaluated.
In the first example, if A is true, the logical expression
is true; otherwise, it is false. In the second example, if both
A and B are true, the logical expression is true; otherwise, it
is false. In the third example, if C is greater than D, and X
is less than or equal to Y, the logical expression is true;
otherwise, it is false.
Logical operations (.AND., .OR., and so on) can only be
performed on logical data types (accepting only .TRUE. or
.FALSE.).
The following are examples of logical expressions:
E.OR.F
E.NEQV.F
G.EQV.H
.NOT.R
U.AND..NOT.V
During execution, these logical expressions are evaluated
as follows:
The expression E.OR.F is true if either E or F are
true.
The expression E.NEQV.F is true if E is true and F is
false, or if E is false and F is true.
The expression G.EQV.H is true if both G and H are true
or false.
The expression .NOT.R is true if R is false.
The expression U.AND..NOT.V is true if U is true and V
is false.
In the last example, note that each one of the logical
operators AND and NOT is delimited by periods. Also, note that
only the operator .NOT. can immediately follow any of the other
logical operators.
An example of a logical expression that includes a relational expression is :
(X.GE.45..AND.A.NEQV.B)
The combined expression is true if the relational expression
X.GE.45. and the logical expression A.NEQV.B are both true.
The logical and relational expressions introduced in this
section are placed within parentheses in the block IF statement
(exp).
4.2 BLOCK IF CONSTRUCT
A block IF construct consists of one or more blocks
separated by the partial statements
IF (exp) THEN
ELSE IF (exp) THEN
ELSE, and
END IF,
in that specific order. Therefore, a block IF construct always begins with the partial statement IF (exp) THEN, and ends
with the partial statement END IF.
The partial statement ELSE IF (exp) THEN can be repeated
zero or more times. The partial statement ELSE is optional; if
included, it can only appear once in a given block IF construct
(excluding nesting--see Nested Block IF Constructs later in
this section).
In general, at most one of the blocks contained within the
block IF construct is executed. However, if the construct
includes the optional ELSE statement, exactly one of the blocks
is executed. The logical expressions (exp) are evaluated in
sequential order until either
In any of these two
cases, the block immediately following is executed and this
completes the execution of the entire block IF construct. In
the first case, remaining ELSE IF (exp) THEN statements, if
any, are not evaluated. If no true value is found and no ELSE
statement is encountered, the execution of the block IF
construct is completed with out the execution of any block.
The following are examples of block IF constructs:
Example 1
IF (exp1) THEN
... !Block 1
ELSE IF (exp2) THEN
... ! Block 2
END IF
Example 2
IF (exp1) THEN
... ! Block 1
ELSE IF (exp2) THEN
... ! Block 2 ELSE
... ! Block 3
END IF
In these examples, the words exp1 and exp2 enclosed in
parentheses stand for logical expressions. The symbol ...
followed by an appropriate trailing comment stands for a given
block, i.e., a set of executable statements that is treated as
a unit.
The following is an example of a block IF construct
containing a block:
IF (A.GT.0.) THEN
B= SQRT(A) ! These two statements
C= A + B ! form a block
END IF
The following rules apply for block IF contructs:
The partial statements ELSEIF (exp) THEN and ELSE can
have statement labels but these cannot be referenced, because
the partial statements are in the middle of the block
construct.
The partial statement END IF can have a statement label; however, this can only be referenced from the block
immediately preceding the END IF.
Control can be transferred out of a block by means of
the GO TO statement (see Section 4.4).
Control cannot be transferred into a block, i..e,
without passing first through the appropriate IF (exp) THEN
partial statement.
The following examples further illustrate the block IF
construct.
Example 1
IF(K.EQ.L) THEN
... ! Block 10
END IF If
If the relational expression (K.EQ.L) is true, block 10 is
executed; otherwise, block 10 is bypassed.
Example 2
IF (X.LE.150.) THEN
... ! Block 20
ELSE IF (X.LE.250.) THEN
... ! Block 21
END IF
If the relational expression (X.LE.150.) is true, block 20
is executed; otherwise, if the expression (X.LE.250.) is true,
block 21 is executed; otherwise, all blocks are by passed. At
most one (1) block is executed per block IF construct.
Example 3
IF (X.LE.150.) THEN
... ! Block 30
ELSE IF (X.LE.250.) THEN
... ! Block 31
ELSE IF (X.LE.350.) THEN
... ! Block 32
END IF
If the relational expression (X.LE.150.) is true, block 30
is executed; otherwise, if the expression (X.LE.250.) is true,
block 31 is executed; otherwise, if the expression (X.LE.350.)
is true, block 32 is executed; otherwise, all blocks are
bypassed. At most one (1) block is executed per block IF
construct. Note that once an expression is found to be true,
the rest are not evaluated.
Example 4
IF (X.LE.XLIMIT) THEN
... ! Block 40 ELSE ... ! Block 41
END IF
If the relational expression (X.LE.XLIMIT) is true, block 40
is executed; otherwise, block 41 is unconditionally executed
due to the presence of the ELSE statement.
Example 5
IF (X.LE.375.) THEN
... ! Block 50
ELSE IF(X.LE.625.) THEN
... ! Block 51 ELSE ... ! Block 52
END IF
If the expression (X.LE.375.) is true, block 50 is exe
cuted; otherwise, if the expression (X.LE.625.) is true, block
51 is executed. If neither of the above are found to be true,
block 52 is unconditionally executed.
Example 6
IF (X.LE.375.) THEN
... ! Block 60
ELSE IF (X.LE.625.) THEN
... ! Block 61
ELSE IF (X.LE.900.) THEN
... ! Block 62
ELSE ... ! Block 63
END
IF If the expression (X.LE.375.) is true, block 60 is executed; otherwise, if the expression (X.LE.625.) is true, block
61 is executed; otherwise, if the expression (X.LE.900.) is
true, block 62 is executed. If none of the above are found to
be true, block 63 is unconditionally executed.
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Things to watch for with regard to block IF constructs:
- Make sure that the expressions in parentheses,
individually and collectively, follow a clear logical pattern
that leads to a logical answer. Otherwise, the block IF
construct may fail to accomplish its intended purpose.
- Remember to always end a block IF construct with an
END IF statement. This is a common source of error, which may
be difficult to detect.
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Nested Block IF Constructs
It is possible to nest two or more block IF constructs,
i.e., to insert one block IF construct inside another block IF
construct. However, the nested block IF should be completely
contained within one block of the nesting block IF. That is,
the nested block IF should not overlap blocks of the nesting
block IF. There is no limit to the number of nestings allowed
in block IF constructs, provided the no-overlap rule is
strictly adhered to. The following examples illustrate the use
of nested block IF constructs.
Example 1
IF (A.LE.3.5) THEN
...
! Block 10
ELSE IF (A.LE.5.5) THEN
... ! Block 20 IF (K.EQ.1)
THEN !Nested block
... ! Block 21
END IF ! Nested block
ELSE
...
! Block 30
END IF
If the relational expression (A.LE.3.5) is
true, block 10 is executed; otherwise, if the expression
(A.LE.5.5) is true, block 20 and the nested block IF that
follows it (indented here only for clarity), including block
21, are executed. If neither (A.LE.3.5) nor (A.LE.5.5) is true,
block 30 is un conditionally executed.
It is good programming
practice to label nested block IF constructs with trailing
comments to help identify nested from nesting block IF
constructs. Following this practice, the preceding example
would look like this:
Example 2
IF (A.LE.3.5) THEN ! 100
... !
Block 10
ELSE IF (A.LE.5.5) THEN ! 101
... ! Block 20
IF
(K.EQ.1) THEN ! 200
... ! Block 21
END IF ! 201
ELSE ! 102
...
! Block 30
END IF ! 103
It is seen that the 100 series numeric
trailing comments mark the nesting (outer) block IF. Likewise,
the 200 series mark the nested (inner) block IF construct.
4.3 LOGICAL IF STATEMENT
Unlike the block IF construct, which
conditionally executes a block, the logical IF statement
conditionally executes a single statement. It takes the form
IF
(exp) execstat
where exp is a logical expression and execstat
is any executable statement, excluding IF and DO (see Chapter
7). During execution, if the logical expression exp within the
parentheses is true, the statement execstat is executed; otherwise, the statement execstat is bypassed.
The following are
examples of logical IF statements:
IF (B) X= Y + Z
IF (C.GT.4.)
STOP
IF (D.AND.E) IFLAG= 1
IF (F.EQV.G) KOUNT= KOUNT + 1
Note
the following:
In the first example, if the logical
expression B is true, the statement X= Y + Z is executed.
- In
the second example, if the relational expression C.GT.4. is
true, the statement STOP is executed.
In the third
example, if the logical expression D.AND.E is true, the
statement IFLAG= 1 is executed.
In the fourth example,
if the logical expression F.EQV.G is true, the statement KOUNT=
KOUNT + 1 is executed. Note that the value of KOUNT is being
incremented by 1 (see Section 5.2).
A logical IF can be readily
converted to a block IF. For instance, the statement
IF
(C.GT.4.) STOP
can alternatively be written in the following
form:
IF (C.GT.4.) THEN
STOP
ENDIF
While the block IF construct
form is longer, it is usually preferred because it leads to a
more readable program. Too many logical IF statements result in
a disruptive and difficult-to-read program. Therefore, it is
good programming practice to avoid the use of the logical IF
statement.
4.4 GO TO AND CONTINUE STATEMENTS GO TO Statement
The GO TO statement is used to transfer control to another
statement located elsewhere in the same program unit. It has
the form
GO TO statnum
where statnum is a valid statement label
in the same program unit as the GO TO statement. Execution of
a GO TO statement causes the statement identified by the label
to be executed next. For instance, execution of the statement
GO TO 20
causes statement 20 to be executed next. The GO TO
statement can appear by itself, or forming an intrinsic part of
a logical IF, as follows:
IF(N.EQ.L) GO TO 40
In this example,
if the relational expression N.EQ.L is true, control branches
to statement 40.
It is good programming practice to use the GO
TO statement sparingly, only when absolutely necessary. In
addition, the logical IF/GO TO combination is highly
disruptive, and its use should be minimized. Often it is better
to use a block IF construct instead of a series of logical
IF/GO TO statements.
CONTINUE Statement
Execution of a CONTINUE
statement has no effect. The CONTINUE statement is usually
placed in between two executable statements or groups of
executable statements. It has the form:
CONTINUE
Upon execution
of this statement, control transfers to the statement
immediately following.
When preceded by an appropriate
statement label, the CONTINUE statement can serve as the
destination of a logical IF/GO TO statement or as the last
statement of a DO loop (see Chapter 7). For example:
IF
(N.EQ.L) GO TO 50
WRITE (6,*) X,Y,Z
50 CONTINUE
If the
relational expression N.EQ.L is true, control branches to
statement 50, and the statement WRITE(6,*) X,Y,Z is effectively
bypassed.
GO TO-CONTINUE Loop
The GO TO and CONTINUE statements
can be used to set up a loop construct to execute a block more
than once. The loop works by transfering control from the
bottom of the block (using a GO TO statement) to the top of the
block (usually a CONTINUE statement). Thus, the execution of
the block is repeated as many times as needed (See examples
below). Other more advanced types of loop constructs are
accomplished with the DO and DO WHILE statements (Chapter 7).
An example of the GO TO-CONTINUE loop is:
DATA N /0/
10
CONTINUE ! Top of loop
N= N +1
READ(5,*) A, B X= A*B
WRITE(6,*)
X
IF (N.EQ.8) STOP
GO TO 10 !
Bottom of loop
This example
initializes a counter N with the value 0, and sets up a GO
TO-CONTINUE loop to read two variables A and B, calculate X=
A*B, and write X. Each time control goes through the loop, the
counter N is incremented by 1. Execution stops when N = 8,
i.e., after completion of 8 passes through the loop.
The
logical IF statement is used to terminate execution (with the
STOP statement, as in the previous example) or to exit the loop
when appropriate (with a GO TO statement, as in the next
example). Without such loop stop or exit, the loop would
continue to be executed indefinitely, which is not desirable. A
loop that executes indefinitely is referred to as an infinite
loop. Identifying and fixing an infinite loop is part of normal
debugging in source program development.
An example of a loop
exit via a GO TO is:
DATA N /0/
10 CONTINUE ! Top of loop
N= N
+1
READ(5,*) A, B
X= A*B
WRITE(6,*) X
IF (N.EQ.8) GO TO 20 !
Loop exit
GO TO 10
! Bottom of loop
20 CONTINUE
An example of
an infinite loop is:
DATA N /0/
10 CONTINUE ! Top of loop
N= N
+1
READ(5,*) A, B
X= A*B
WRITE(6,*) X
GO TO 10
! Bottom of loop
Note that this loop would continue to execute indefinitely,
with nothing to stop it. This infinite loop would tie up the
processor, effectively distracting it from completing other
useful tasks.
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Things to keep in mind with respect to the GO
TO-CONTINUE loop:
- The GO TO-CONTINUE loop is used here
as a way to introduce programming logic rather than as a
preferred way to program an application.
- In practice,
most GO TO-CONTINUE loops can be readily replaced by the more
compact and efficient DO and DO WHILE loops treated in Chapter
7.
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4.5 ARITHMETIC IF STATEMENT
Unlike the logical
IF/GO TO combination, which conditionally transfers control to
a statement located elsewhere in the program unit, the
arithmetic IF statement transfers control to at least one and
at most three statements.
The arithmetic IF statement has the
form
IF (numexp) label1, label2, label3
where numexp is a
numeric expression, and label1, label2, and label3 are the
first, second, and third labels, respectively. Each of these
must be a valid statement label in the same program unit as the
given arithmetic IF statement.
Execution of an arithmetic IF
statement causes the numeric expression numexp to be evaluated,
followed by a transfer of control:
- If numexp is less
than zero, control branches to statement label1.
- If
numexp is equal to zero, control branches to statement label2.
- If numexp is greater than zero, control branches to
statement label3.
The same label may appear more than once in
one arithmetic IF statement.
The following are two examples of
arithmetic IF statements:
IF (A) 10,20,30
IF (L-M) 40,40,50
In
the first example, if A is less than 0., control branches to
statement 10. If A is equal to 0., control branches to
statement 20. If A is greater than 0., control branches to
statement 30.
In the second example, if L-M is less than or
equal to 0, control branches to statement 40. If L-M is
greater than 0, control branches to statement.
Note that the
arithmetic IF statement has been declared as obsolescent by the
Fortran 90 standard. Therefore, its use should be avoided in
new program development, and is described here only for
completeness.
4.6 EXAMPLE PROGRAMS
Example Program 1: Logical
Expressions
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C234567890
PROGRAM LOGEXP
LOGICAL A,B
DATA A,B,X,Y,Z
/.TRUE.,.FALSE.,15.,24.,30./
IF(A.EQV.B.AND.X.GE.Y) THEN
WRITE(6,*) 'FIRST TEST PASSED'
ELSE
WRITE(6,*) 'FIRST TEST DID
NOT PASS'
END IF IF (X.LT.Y.OR.Y.LT.Z) THEN
WRITE(6,*) 'SECOND
TEST PASSED'
END IF
END |
This example accomplishes the following tasks:
- Declares two logical variables A and B.
- Initializes
A as .TRUE. and B as .FALSE.
- Initializes three
implicitly declared real variables X = 15., Y = 24., and Z =
30, in a DATA statement.
- Tests to see if both of the
following conditions are true: (a) A and B have the same value;
and (b) X is greater than or equal to Y. If both conditions are
true, it writes FIRST TEST PASSED; otherwise, it writes FIRST
TEST DID NOT PASS.
- Tests to see if X is less than Y, or
Y is less than Z. If this is true, it writes SECOND TEST
PASSED.
Note that this is only an example. In a real-world situation, some or all of the variables would be read as input
rather than be initialized with a DATA statement. Also, note
that some processors may implicitly initialize all logical
variables as .FALSE., making such initialization redundant.
Example Program 2: Nested Block IF Construct
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C234567890
PROGRAM ABCDEF
DATA A,B,C,D,E,F /3.,5.,7.-10.,-20.,-40./
IF (A.LT.B) THEN ! 100
WRITE(6,*) 'A IS LESS THAN B'
ELSEIF (B.LE.C) THEN ! 101
WRITE(6,*) 'B IS LESS THAN OR EQUAL TO C'
ELSE ! 102
IF
(D+E.GT.F) THEN ! 200
WRITE(6,*) '(D + E) IS GREATER THAN F'
END IF ! 201
END IF ! 103
END |
This example
accomplishes the following tasks:
Initializes six
implicitly declared real variables A, B, C, D, E, and F.
Tests
to see if A is less than B. If so, it writes the message A IS
LESS THAN B.
Otherwise, it tests to see if B is less
than or equal to C. If so, it writes the message B IS LESS THAN
OR EQUAL TO C.
Otherwise, it unconditionally executes
the nested block IF that follows the ELSE ! 102 statement. It
tests to see if D + E is greater than F. If so, it writes the
message (D + E) IS GREATER THAN F.
Again, this is only an
example. In a real-world situation, some or all of the
variables would be read as input rather than be initialized
with a DATA statement. Also, the presence of numeric trailing
comments helps identify the nested block (200 series) from the
nesting block IF construct (100 series). Note that every block
IF construct finishes with its own END IF (partial) statement,
and every program finishes with it own END statement.
4.7 SUMMARY
The conditional IF statements are used to conditionally
execute
--by using the block IF construct,
which consists of the partial statements
IF (exp) THEN
ELSEIF (exp) THEN
ELSE
END IF
--block IF constructs
may be nested within other block IF constructs
--block IF
constructs are the most commonly used conditional statements
--by using the logical IF statement
--the
logical IF has limited application, but remains in use
--by using a GO TO statement as part of a
logical IF statement, as in IF(N.EQ.L) GO TO 40
--by using a
logical IF as a means to exit a GO TO- CONTINUE loop, as in
IF(N.EQ.8) STOP
--by using the arithmetic IF statement
--the
arithmetic IF statement has been declared as obsolescent by
the Fortran 90 standard; therefore, its use in new applications
is discouraged.
CHAPTER 4 -- PROBLEMS
The three dimensions of a
box are: (1) length, (2) width, and (3) height. Write an
interactive program that uses logical variables to accomplish
the following tasks:
Using DATA statements, initialize the
specified minimum width/length ratio as 0.5, maximum
width/length ratio as 1.0, minimum volume as 950 cubic inches,
and maximum volume as 1050 cubic inches.
Read the width,
length, and height of a tested box (in inches), and calculate
its width/length ratio and volume.
Determine if the box
width/length ratio is between the specified limits. Write the
answer, either true (T) or false (F), preceded by an
appropriate message such as: WIDTH/LENGTH CONSTRAINT IS
SATISFIED?: F
Determine if the box volume is between the
specified limits. Write the answer, either true (T) or false
(F), preceded by an appropriate message such as: VOLUME
CONSTRAINT IS SATISFIED?: T
Determine if both width/length
ratio and volume constraints are satisfied. Write the answer,
either true (T) or false (F), preceded by an appropriate
message such as: BOTH WIDTH/LENGTH AND VOLUME CONSTRAINTS ARE
SATISFIED?: F
Test the program with the following data sets:
LENGTH WIDTH HEIGHT
12. 8. 11.
10.5 11. 9.0
10. 6. 17.5
The
density of a sample cylinder is being tested for compliance
with a set of specifications. Write an interactive program that
uses logical vari ables to accomplish the following tasks:
Using DATA statements, initialize the specified minimum and
maximum densities of the cylinder as 30 and 50 lbs/cu ft,
respectively, and the base diameter, height, and weight of a
specification cone as 2 ft, 4 ft, and 120 lbs, respectively.
Read the diameter and height (in ft) and weight (lbs), of a
sample cylinder, and calculate its density.
Determine if the
cylinder density is between the specified limits. Write the
answer, either true (T) or false (F), preceded by an
appropriate message such as: FIRST DENSITY CONSTRAINT IS SATISFIED?:
T
Determine if the cylinder density is less than or equal
that of the specification cone. Write the answer, either true
(T) or false (F), preceded by an appropriate message such as:
SECOND DENSITY CONSTRAINT IS SATISFIED?: F
Determine if both
density constraints are satisfied. Write the answer, either
true (T) or false (F), preceded by an appropriate message such
as: BOTH CONSTRAINTS ARE SATISFIED?: F
Test the program with
the following data sets:
CYL. DIAMETER
CYL. HEIGHT CYL.WEIGHT
0.5 1. 30.
1. 2. 60.
2. 4. 180.
An instructor wants to
convert numeric grades to letter grades, and has chosen for
this purpose the following grading scale: A= 100-90; B= 89- 80;
C= 79-70; D= 69-60; F= 59-0. Write a program to accomplish the
following tasks. Use a nested block IF for this purpose.
Read, from an input file, one at a time, 15 numeric grades;
assign a corresponding letter grade; and write the letter grade
to an output file. [Hint: Set up a GO TO-CONTINUE loop to
execute a block 15 times].
If the input numeric grade is out
of range, write an appropriate message such as: ERROR IN
NUMERIC GRADE.
Test the program with the following data set:
97, 78, 56, 100, 902, 45, 67, 72, 89, 71, 69, 85, 92, 80, and
79.
An international traveler is allowed by an airline
carrier two check-in bags and one carry-on. The check-in bags
cannot weigh more than 70 lbs each. The sum of the dimensions
of the check-in bags (length plus width plus height) cannot
exceed, for the first bag, 62 inches, and for the second, 45
inches. The third bag (the carry-on) cannot weigh more then 30
lbs, the sum of its dimensions cannot exceed 45 inches, and its
longer dimension cannot exceed 22 inches. Write a program to
read, from an input file, one-at-a-time, 5 complete baggage
data sets, and to determine whether all baggage restrictions
have been satisfied. Write the answer to the screen, either YES
or NO, preceded by an appropriate message such as: ALL BAGGAGE
OK?: YES, or, ALL BAGGAGE OK?: NO. [Hint: Set up a GO
TO-CONTINUE loop to execute a block 5 times]. Test your program
with the following data set:
L1 W1 H1 lbs L2 W2 H2 lbs L3 W3 H3
lbs
36. 24. 6. 66. 24. 16. 5. 45. 17. 12. 8. 29.
35. 18. 6. 70.
22. 14. 6. 40. 16. 12. 6. 25.
30. 16. 6. 55. 24. 14. 5. 67. 14.
10. 5. 21.
34. 16. 6. 72. 23. 15. 6. 39. 14. 10. 5. 43.
35. 15.
8. 80. 20. 10. 10. 61. 14. 10. 5. 23.
The water department of
a major city has decided to implement a new rate structure that
reflects the perceived need for water conservation. The new
rates are: $ 0.95/HCF (100 cubic feet) for the first 20 HCF, $
1.15/HCF for any additional amounts over 20 HCF, up to 40 HCF,
and $ 1.85/HCF for any additional amounts over 40 HCF. The
sewer rate is a flat rate of $36.00 per billing period. Write a
program to read from an input file, one-at-a-time, six
unformatted data sets, each consisting of a consumer's name,
address, and water consumption (in HCF) per billing period;
calculate the total billing amount, including water and sewage;
and write to an output file (using an unformatted WRITE) the
con sumer's name, address, water consumption, and amount
billed. For any consumer whose consumption is 20 HCF or less,
the following message should accompany the bill: THANK YOU FOR
YOUR EFFORTS IN WATER CONSERVATION. [Hint: Initialize all
constants in DATA statements. Set up a block IF construct and a
GO TO-CONTINUE loop to execute six times]. Test your program
with the following data set:
NAME ADDRESS CONSUMPTION (HCF)
Smith, J. W. 1345 Samantha Ave. 35
Jones, P. T. 675 Thunderhead
Ave. 56
Davis, H. K. 3355 Ruffin Ave. 49
Peters, L. D. 1262 Dax
Ave. 19
Garcia, B. R. 6734 Carmel Ave. 27
Thomas, J. K. 894
Springfield Dr. 67
Repeat Problem 5, but with the provision
that any consumer showing a consumption of more than 60 HCF per
billing period pay an additional sewer charge of $ 12.00.
Do
Problem 3 of Chapter 3 (E banner) using a block IF construct
and a GO TO-CONTINUE loop.
Do Problem 14 of Chapter 3
(tic-tac-toe board) using a block IF con struct and a GO
TO-CONTINUE loop.
Do Problem 15 of Chapter 3 (numeric design)
using a block If construct and a GO TO-CONTINUE loop.
The
electric utility of a major city is changing its rates to
reflect increasing energy costs. The new rates are: $
0.095/kwh (kilowatt-hour) for the first 250 kwh (baseline
usage), and $ 0.125/kwh for any additional amounts over 250
kwh. Write a program to read from an input file, one at a time,
six unformatted data sets, each consisting of a consumer's
name, address, and energy consumption (in kwh) per billing
period; calculate the amount to be billed; and write to an
output file (using an unformatted WRITE) the consumer's name,
address, energy consumption, and amount billed. For any
consumer whose consumption is 250 kwh or less, the following
message should accompany the bill (to the right): THANK YOU FOR
YOUR EFFORTS IN ENERGY CONSERVATION. [Hint: Initialize all
constants in DATA statements. Set up a block IF construct and a
GO TO-CONTINUE loop to execute six times]. Test your program
with the following data set:
NAME ADDRESS CONSUMPTION (kwh)
Smith, J. W. 1345 Samantha Ave.
535
Jones, P. T. 675 Thunderhead
Ave.
856
Davis, H. K. 3355 Ruffin Ave.
1249
Peters, L. D. 1262 Dax
Ave.
219
Garcia, B. R. 6734 Carmel Ave.
627
Thomas, J. K. 894
Springfield Dr.
167
Repeat Problem 10, but
with the provision that any consumer showing a consumption of
more than 750 kwh pay a surcharge of $ 0.025/kwh.
Write an
interactive program that reads an integer less than or equal to
30, calculates its factorial, and writes the result to the
screen. Use the following output form: THE FACTORIAL OF ___ IS
_______. If the entered number is greater than 30, write the
following message to the screen: ENTERED NUMBER IS OUT OF
RANGE.
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