S.J.S. tutorial 3: loops that use the for construct
SECTION(3, Tutorial 3)
m5_question(BO(Question 3.1a: For loops that count up in steps of
one.) Study the following code and verify that it prints out TT("2
3 4 5 6 7 8 9 10") by compiling and running it. Notice that the
SYSTEM_OUT_PRINT function call doesn't print a carriage return after
printing the argument value. That is why the SYSTEM_OUT_PRINTLN
function call is needed at the end of the EM(for) loop, to print a
carraige return at the end of the line. Also note the use of the plus
sign to concatenate a string and the number to produce another string.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR INT i=NUMB(2); LTEQ(i,NUMB(10)); i=i+NUMB(1)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.1b:) Change the for loop to print out
TT("5 6 7 8 9 10").)
m5_question(BO(Question 3.1c:) Change the for loop to print out
TT("234 235 236 237 238").)
m5_question(BO(Question 3.1d:) Change the for loop to print out
TT("48 49 50 ... 75 76").)
m5_question(BO(Question 3.1e:) Change the for loop to print out
TT("-5 -4 -3 -2 -1 0 1 2 3").)
m5_question(BO(Question 3.2a: For loops that count up in steps
greater than one.) Study the following code and verify that it
prints out TT("10 15 20 25 30 35 40") by compiling and running it.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR INT VARI(i)=NUMB(10); LTEQ(i,NUMB(40)); i=i+NUMB(5)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.2b:) Change the for loop to print out
TT("20 25 30 35 40").)
m5_question(BO(Question 3.2c:) Change the for loop to print out
TT("100 105 110 115 120 125").)
m5_question(BO(Question 3.2d:) Change the for loop to print out TT("2 4 6 8 10 12
14").)
m5_question(BO(Question 3.2e:) Change the for loop to print out
TT("10 13 16 19 22 25").)
m5_question(BO(Question 3.3a: For loops that count down in steps
of one.) Study the following code and verify that it prints out
TT("10 9 8 7 6 5 4 3 2 1") by compiling and running it.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR INT VARI(i)=NUMB(10); GTEQ(i,NUMB(1)); i=i-NUMB(1)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.3b:) Change the for loop to print out
TT("10 9 8 7 6 5 4").)
m5_question(BO(Question 3.3c:) Change the for loop to print out TT("20 19 18 17
16 15 14 13 12").)
m5_question(BO(Question 3.3d:) Change the for loop to print out TT("66 65 64
... 47").)
m5_question(BO(Question 3.3e:) Change the for loop to print out TT("3 2 1 -1 -2
-3 -4 -5 -6 -7").)
m5_question(BO(Question 3.4a: For loops that count down in steps
greater than one.) Study the following code and verify that it
prints out TT("100 90 80 70 60 50 40 30 20") by compiling and running
it.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR INT VARI(i)=NUMB(100); GTEQ(i,NUMB(20)); i=i-NUMB(10)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.4b:) Change the for loop to print out
TT("80 70 60 50 40 30 20").)
m5_question(BO(Question 3.4c:) Change the for loop to print out TT("500 490 480
470 460").)
m5_question(BO(Question 3.4d:) Change the for loop to print out TT("10 8 6 4 2 0").
)
m5_question(BO(Question 3.4e:) Change the for loop to print out TT("33 28 23 18
13 8 3").)
m5_question(BO(Question 3.5a: For loops that use floating point
numbers to count.) Study the following code and verify that it
prints out TT("1.1 2.2 3.3 4.4") by compiling and running it. The
type name EM(double) is short for EM(double precision floating point).
It is natural to ask: why not use single precision floating point?
The answer to this question is that double precision floating point
gives fewer compilation errors than single precision floating point
does.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR DOUBLE VARI(i)=NUMB(1.1); LTEQ(i,NUMB(4.4)); i=i+NUMB(1.1)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.5b:) Change the for loop to print
out TT("0 2.2 4.4 6.6"). Note that rounding errors may prevent you
from getting this exact answer. Also note that the answer to this
question is not what you would naively expect without running the
code.)
m5_question(BO(Question 3.5c:) Change the for loop to print out TT("-30 -19.9
-9.8 0.3 10.4 20.5").)
m5_question(BO(Question 3.5d:) Change the for loop to print
out TT("100.0 96.7 93.4 90.1 86.8 83.5 80.2 76.9").)
m5_question(BO(Question 3.5e:) Change the for loop to print
out TT("-100.0 -105.5 -111.0 -116.5").)
m5_question(BO(Question 3.6a: For loops that use chars to count.)
Study the following code and verify that it prints out TT("a b c d e f
g h i j k l m n o p q r s t u v w x y z") by and running it.
m4_begin_indent
NU()CLASS CLSS(ForTest) EOL
BEGIN EOL
PD BEGIN_MAIN EOL
PD PD FUR (VAR CHAR VARI(i)=STRI('a'); LTEQ(i,STRI('z')); i=i+NUMB(1)) SYSTEM_OUT_PRINT(STRI(" ") + i); EOL
PD PD SYSTEM_OUT_PRINTLN(); EOL
PD END_MAIN EOL
END EOL
m4_end_indent
)
m5_question(BO(Question 3.6b:) Change the for loop to print
out TT("a b c d e f").)
m5_question(BO(Question 3.6c:) Change the for loop to print
out TT("z y x w v u t s r q p o n m l k j i h g f e d c b a").)
m5_question(BO(Question 3.6d:) Change the for loop to print
out TT("p o n m l k j i h").)
m5_question(BO(Question 3.6e:) Change the for loop to print
out TT("A [[B]] C D E [[F]] G H I J K L M N O P Q R [[S]] T U V W X Y Z").)
