Chapter 4 Code Lab

Front 1

The area of a square is stored in a double variable named area. Write an expression whose value is length of one side of the square.

Back 1

Math.sqrt(area)

Front 2

The area of a square is stored in a double variable named area. Write an expression whose value is length of the diagonal of the square.

Back 2

Math.sqrt(area*2)

Front 3

The length of a rectangle is stored in a double variable named length, the width in one named width. Write an expression whose value is the length of the diagonal of the rectangle.

Back 3

Math.sqrt(Math.pow(length,2) + Math.pow(width,2))

Front 4

If a right triangle has sides of length A, B and C and if C is the largest, then it is called the "hypotenuse" and its length is the square root of the sum of the squares of the lengths of the shorter sides (A and B). Assume that variables a and b have been declared as doubles and that a and b contain the lengths of the shorter sides of a right triangle: write an expression for the length of the hypotenuse.

Back 4

Math.sqrt(Math.pow(a,2) + Math.pow(b,2))

Front 5

The Math class provides a static method , max, that accepts twoint arguments and returns the value of the larger one.

Two int variables ,population1 and population2, have already been declared and initialized .

Write an expression (not a statement !) whose value is the larger of population1 and population2 by calling max.

Back 5

Math.max(population1, population2)

Front 6

Back 6

Math.sqrt(Math.sqrt(x))

Front 7

The Math class provides a static method , max, that accepts two int arguments and returns the value of the larger one.

Four int variables , population1, population2, population3, and population4 have already been declared and initialized .

Write an expression (not a statement !) whose value is the largest of population1, population2, population3, and population4 by calling max.

Back 7

Math.max(Math.max(population1,population2),Math.max(population3,population4))

Front 8

Write a character literal representing the (upper case) letter A.

Back 8

'A'

Front 9

Write a character literal representing a comma.

Back 9

','

Front 10

Write a character literal representing the digit 1.

Back 10

'1'

Front 11

Write a literal representing the character whose unicode value is 65.

Back 11

'A'

Front 12

Write a literal representing the largest character value .

Back 12

65535

Front 13

The character escape sequence to force the cursor to go to the next line is:

Back 13

\n

Front 14

The character escape sequence to force the cursor to advance forward to the next tab setting is:

Back 14

\t

Front 15

The character escape sequence to represent a single quote is

Back 15

\'

Front 16

The character escape sequence to represent a double quote is:

Back 16

\"

Front 17

Declare a character variable named c.

Back 17

char c;

Front 18

Java represents characters using

Back 18

Unicode

Front 19

Write a String constant consisting of exactly 5 exclamation marks.

Back 19

"!!!!!"

Front 20

Write a String constant consisting of exactly one character -- any character will do.

Back 20

"d"

Front 21

Write a String constant that is the empty string .

Back 21

""

Front 22

Declare a String variable named mailingAddress.

Back 22

String mailingAddress = new String();

Front 23

Write the declaration of a String variable named title.

Back 23

String title = new String();

Front 24

Write the declaration of three String variables named win, place, and show.

Back 24

String win = new String();

String place = new String();

String show = new String();

Front 25

Write the declaration of a String variable named foreground and initialize it to "black".

Back 25

String foreground = new String("black");

Front 26

Declare a String variable named oneSpace, and initialize it to a String consisting of a single space.

Back 26

String oneSpace = " ";

Front 27

Write the declaration of two String variable named background and selectionColor and initialize them to "white" and "blue" respectively.

Back 27

String background="white";

String selectionColor="blue";

Front 28

Declare a String variable named empty, and initialize it to the empty String .

Back 28

String empty = new String();

Front 29

Assume that word is a String variable . Write a statement to display the message "Today's Word-Of-The-Day is: " followed by the value of word. The message and the value of word should appear together, on a single line on standard output .

Back 29

System.out.println("Today's Word-Of-The-Day is: " + word);

Front 30

Assume that message is a String variable . Write a statement to display its value on standard output .

Back 30

System.out.println(message);

Front 31

Assume that the String variable named foreground has already been declared . Assign it the value "red".

Back 31

foreground = "red";

Front 32

Assume that theString variable named text has already been declared . Assign to it the empty string .

Back 32

text = "";

Front 33

There are two String variables , s1 and s2, that have already been declared and initialized . Write some code that exchanges their values .

Declare any other variables as necessary.

Back 33

String temp = new String();

temp = s1;

s1 = s2;

s2 = temp;

Front 34

Given three String variables that have been declared and given values , firstName, middleName, and lastName, write an expression whose value is the values of each these variables joined by a single space. So if firstName, middleName, and lastName, had the values "Big", "Bill", and "Broonzy", the expression 's value would be "Big Bill Broonzy". Alternatively, if firstName, middleName, and lastName, had the values "Jerry", "Lee", and "Lewis", the expression 's value would be "Jerry Lee Lewis

Back 34

firstName + " " + middleName + " " + lastName

Front 35

Given a String variable address, write a String expression consisting of the string "http://" concatenated with the variable 's String value . So, if the variable refers to "www.turingscraft.com", the value of the expression would be "http://www.turingscraft.com".

Back 35

"http://" + address

Front 36

Write an expression that concatenates the String variable suffix onto the end of the String variable prefix .

Back 36

prefix + suffix

Front 37

Given a String variable word, write a String expression that parenthesizes the value of word. So, if word contains "sadly", the value of the expression would be the String "(sadly)"

Back 37

"(" + word + ")"

Front 38

Given four int variables that have been declared and given values , octet1, octet2, octet3, and octet4, write a String expression whose value is the String equivalent of each these variables joined by a single period (.) So if octet1, octet2, octet3, and octet4, had the values 129, 42, 26, and 212 the expression 's value would be "129.42.26.212". Alternatively, if octet1, octet2, octet3, and octet4, had the values 192, 168, 1and 44 the expression 's value would be "192.168.1.44".

Back 38

octet1 + "." + octet2 + "." + octet3 + "." + octet4

Front 39

Given three String variables that have been declared and given values , gold, silver, and bronze, write an expression whose value is the values of each these variables joined by a newline character . So if gold, silver, and bronze, had the values "Arakawa", "Cohen", and "Slutskaya", the expression , if it were printed would have the names "Arakawa", "Cohen", and "Slutskaya" each appearing on a separate line. (Do NOT print anything in this exercise: just write the expression .)

Back 39

gold + "\n" + silver + "\n" + bronze

Front 40

Given three int variables that have been declared and given values , areaCode, exchange, and lastFour, write a String expression whose value is the String equivalent of each these variables joined by a single hyphen (-) So if areaCode, exchange, and lastFour, had the values 800, 555, and 1212, the expression 's value would be "800-555-1212". Alternatively, if areaCode, exchange, and lastFour, had the values 212, 867 and 5309 the expression 's value would be "212-867-5309".

Back 40

areaCode + "-" + exchange + "-" + lastFour

Front 41

Write a statement that reads a word from standard input into firstWord. Assume that firstWord. has already been declared as a String variable . Assume also that stdin is a variable that references a Scanner object associated with standard input.

Back 41

firstWord = stdin.next();

Front 42

Assume that name and age have been declared suitably for storing names (like "Abdullah", "Alexandra" and "Zoe") and ages respectively. Assume also that stdin is a variable that references a Scanner object associated with standard input. Write some code that reads in a name and an age and then prints the message "The age of NAME is AGE" on a line by itself, where NAME and AGE are replaced by the values read in for the variables name and age. For example, if your code read in "Rohit" and 70 then it would print out "The age of Rohit is 70" on a line by itself. There should NOT be a period in the output .

Back 42

name = stdin.next();

age = stdin.nextInt();

System.out.println("The age of " + name + " is " + age);

Front 43

Three business partners are forming a company whose name will be of the form "Name1, Name2 and Name3". However, they can't agree whose name should be first, second or last. Help them out by writing code that reads in their three names and prints each possible combination exactly once, on a line by itself (that is, each possible combination is terminated with a newline character ). Assume that name1, name2 and name3 have already been declared and use them in your code. Assume also that stdin is a variable that references a Scanner object associated with standard input. For example, if your code read in "Larry", "Curly" and "Moe" it would print out "Larry, Curly and Moe", "Curly, Larry and Moe", etc., each on a separate line.

Back 43

name1 = stdin.next();

name2 = stdin.next();

name3 = stdin.next();

System.out.println(name1 + ", " + name2 + " and " + name3);

System.out.println(name1 + ", " + name3 + " and " + name2);

System.out.println(name2 + ", " + name1 + " and " + name3);

System.out.println(name2 + ", " + name3 + " and " + name1);

System.out.println(name3 + ", " + name2 + " and " + name1);

System.out.println(name3 + ", " + name1 + " and " + name2);

Front 44

Assume that name has been declared suitably for storing names (like "Amy", "Fritz" and "Moustafa"). Assume also that stdin is a variable that references a Scanner object associated with standard input. Write some code that reads a value into name then prints the message "Greetings, NAMEVALUE!!!" on a line by itself where NAMEVALUE is replaced the value that was read into name . For example, if your code read in "Hassan" it would print out "Greetings, Hassan!!!" on a line by itself.

Back 44

name = stdin.next();System.out.println("Greetings, " + name + "!!!");

Front 45

Assume that name has been declared suitably for storing names (like "Misha", "Emily" and "Sofia"). Assume also that stdin is a variable that references a Scanner object associated with standard input Write some code that reads a value into name then prints the message "Greetings, NAME " on a line by itself, where NAME is replaced the value that was read into name . For example, if your code read in "Rachel" it would print out "Greetings, Rachel" on a line by itself.

Back 45

name = stdin.next();System.out.println("Greetings, " + name);

Front 46

Given a String variable named sentence that has been initialized , write an expression whose value is the number of characters in the String referred to by sentence.

Back 46

sentence.length()

Front 47

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is the first character of the value of name . So if the value of name were "Smith" the expression 's value would be 'S'.

Back 47

name.charAt(0)

Front 48

Given the String variable str, write an expression that evaluates to the character at index 0 of str.

Back 48

str.charAt(0)

Front 49

Given the String variable name , write an expression that evaluates to the third character of name .

Back 49

name.charAt(2)

Front 50

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is the second character of the value of name . So if the value of name were "Smith" the expression 's value would be 'm'.

Back 50

name.charAt(1)

Front 51

Write an expression that whose value is the fifth character of the String name .

Back 51

name.charAt(4)

Front 52

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is the last character of the value of name . So if the value of name were "Blair" the expression 's value would be 'r'.

Back 52

name.charAt(name.length() - 1)

Front 53

Write an expression that evaluates to true if and only if the string variable s equals the string "end".

Back 53

s.equals("end")

Front 54

Write an expression that evaluates to true if the value of the string variable s1 is greater than the value of string variable s2.

Back 54

s1.compareTo(s2)>0

Front 55

Write an expression that evaluates to true if the value of variable lastName is greater than the string Dexter.

Back 55

lastName.compareTo("Dexter")>0

Front 56

Write an expression that evaluates to true if and only if the string variable s does not equal the String literal end.

Back 56

(!s.equals("end"))

Front 57

Given the String variables name1 and name2, write a fragment of code that assigns the larger of the two to the variable first (assume that all three are already declared and that name1 and name2 have been assigned values ).

(NOTE: "larger " here means alphabetically larger , not "longer". Thus, "mouse" is larger than "elephant" because "mouse" comes later in the dictionary than "elephant"!)

Back 57

Front 58

Given the string variables name1, name2, and name3, write a fragment of code that assigns the largest value to the variable max (assume all three have already been declared and have been assigned values ).

Back 58

Front 59

Assume thats is a String . Write an expression whose value is true if and only if the value ofs would come between "mortgage" and "mortuary" in the dictionary.

Back 59

(s.compareTo("mortgage")>0 && s.compareTo("mortuary")<0)

Front 60

Clunker Motors Inc. is recalling all vehicles in its Extravagant line from model years 1999-2002. Given a variable modelYear and a String modelName write a statement that prints the message "RECALL" to standard output if the values ofmodelYear andmodelName match the recall details.

Back 60

Front 61

Clunker Motors Inc. is recalling all vehicles in its Extravagant line from model years 1999-2002 as well all vehicles in its Guzzler line from model years 2004-2007. Given a variable modelYear and a String modelName write a statement that prints the message "RECALL" to standard output if the values ofmodelYear andmodelName match the recall details.

Back 61

Front 62

Clunker Motors Inc. is recalling all vehicles in its Extravagant line from model years 1999-2002. A boolean variable named recalled has been declared . Given a variable modelYear and a String modelName write a statement that assigns true to recalled if the values ofmodelYear andmodelName match the recall details and assigns false otherwise.

Back 62

Front 63

Clunker Motors Inc. is recalling all vehicles in its Extravagant line from model years 1999-2002 as well all vehicles in its Guzzler line from model years 2004-2007. A boolean variable named recalled has been declared . Given a variable modelYear and a String modelName write a statement that assigns true torecalled if the values ofmodelYear andmodelName match the recall details and assigns false otherwise.

Back 63

Front 64

Given the String variable address, write an expression that returns the position of the first occurrence of the String "Avenue" in address.

Back 64

address.indexOf("Avenue")

Front 65

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is a String containing the first character of the value of name . So if the value of name were "Smith" the expression 's value would be "S".

Back 65

name.substring(0,1)

Front 66

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is a String containing the second character of the value of name . So if the value of name were "Smith" the expression 's value would be "m".

Back 66

name.substring(1,2)

Front 67

Write an expression that results in a String consisting of the third through tenth characters of the String s.

Back 67

s.substring(2,10)

Front 68

Assume that word is a variable of type String that has been assigned a value . Write an expression whose value is a String consisting of the last three characters of the value of word. So if the value of word were "biggest" the expression 's value would be "est".

Back 68

word.substring(word.length() - 3,word.length())

Front 69

Given three String variables that have been declared and given values , firstName, middleName, and lastName, write an expression whose value is the initials of the three names : the first letter of each, joined together. So if firstName, middleName, and lastName, had the values "John", "Fitzgerald", and "Kennedy", the expression 's value would be JFK". Alternatively, if firstName, middleName, and lastName, had the values "Franklin", "Delano", and "Roosevelt", the expression 's value would be "FDR".

Back 69

"" + firstName.charAt(0) + middleName.charAt(0) + lastName.charAt(0)

Front 70

Assume that sentence is a variable of type String that has been assigned a value . Assume furthermore that this value is a String consisting of words separated by single space characters with a period at the end. For example: "This is a possible value of sentence."

Assume that there is another variable declared , firstWord, also of type String . Write the statements needed so that the first word of the value of sentence is assigned to firstWord. So, if the value of sentence were "Broccoli is delicious." your code would assign the value "Broccoli" to firstWord.

Back 70

firstWord = sentence.substring(0,sentence.indexOf(' '));

Front 71

Assume that given , middle and family are three variables of type String that have been assigned values . Write an expression whose value is a String consisting of the first character of given followed by a period followed by the first character of middle followed by a period followed by the first character of family followed by a period: in other words, the initials of the name . So if the values of these three variables were "John" "Fitzgerald" "Kennedy", then the expression 's value would be "J.F.K.".

Back 71

given.charAt(0) + "." + middle.charAt(0) + "." + family.charAt(0) + "."

Front 72

Given a String variable named sentence that has been initialized , write an expression whose value is the the very last character in the String referred to by sentence.

Back 72

sentence.charAt(sentence.length() - 1)

Front 73

Write a sequence of statements that finds the first comma in the String line, and assigns to the variable clause the portion of line up to, but not including the comma. You may assume that an int variable pos, as well as the variables line and clause, have already been declared .

Back 73

pos = line.indexOf(',');

clause = line.substring(0,pos);

Front 74

Assume that sentence is a variable of type String that has been assigned a value . Assume furthermore that this value is a String consisting of words separated by single space characters with a period at the end. For example: "This is a possible value of sentence."

Assume that there is another variable declared , secondWord, also of type String . Write the statements needed so that the second word of the value of sentence is assigned to secondWord. So, if the value of sentence were "Broccoli is delicious." your code would assign the value "is" to secondWord.

Back 74

int start = sentence.indexOf(" ") + 1;

int end = sentence.indexOf(" ", start+1);

secondWord = sentence.substring(start,end);

Front 75

Given a String variable named sentence that has been initialized , write an expression whose value is the index of the very last character in the String referred to by sentence.

Back 75

sentence.length() - 1

Front 76

Assume that name is a variable of type String that has been assigned a value . Write an expression whose value is a String containing the last character of the value of name . So if the value of name were "Smith" the expression 's value would be "h".

Back 76

name.substring(name.length() - 1,name.length())

Front 77

A String variable , fullName, contains a name in one of two formats:

last name , first name (comma followed by a blank), orfirst name last name (single blank)

Extract the first name into the String variable firstName and the last name into the String variable lastName.

Assume the variables have been declared and fullName already initialized . You may also declare any other necessary variables .

Back 77