Chapter 2 Code Lab

Front 1

Given an integer variable count, write a statement that displays the value of count on the screen.Do not display anything else on the screen -- just the value of count.

Back 1

System.out.println(count);

Front 2

Two variables , num and cost have been declared and given values : num is an integer and cost is a double . Write a single statement that outputs num and cost to standard output . Print both values (num first, then cost), separated by a space on a single line that is terminated with a newline character . Do not output any thing else.

Back 2

System.out.println(num + " " + cost + "\n");

Front 3

Given a floating point variable fraction, write a statement that displays the value of fraction on the screen.Do not display anything else on the screen-- just the value of fraction.

Back 3

System.out.println(fraction);

Front 4

Which of the following is NOT a legal identifier?

Back 4

7thheaven (begins with digit)

Front 5

Which of the following IS a legal identifier?

Back 5

______

Front 6

An identifier that cannot be used as a variable name is a

Back 6

reserved word

Front 7

Before a variable is used it must be

Back 7

declared

Front 8

Declare an integer variable named degreesCelsius.

Back 8

int degreesCelsius;

Front 9

Declare two integer variables named profitStartOfQuarter and cashFlowEndOfYear.

Back 9

int profitStartOfQuarter;

int cashFlowEndOfYear;

Front 10

Declare a float variable named price.

Back 10

float price;

Front 11

Declare a double variable named netWeight.

Back 11

double netWeight;

Front 12

Declare two double variables , one named length with a value of 3.5 and the other named width with a value of 1.55.

Back 12

double length = 3.5;

double width = 1.55;

Front 13

Declare an integer variable cardsInHand and initialize it to 13.

Back 13

int cardsInHand = 13;

Front 14

Declare a variable populationChange, suitable for holding numbers like -593142 and 8930522.

Back 14

int populationChange;

Front 15

Declare a variable x, suitable for storing values like 3.14159 and 6.02E23.

Back 15

float x;

Front 16

Declare a variable temperature and initialize it to 98.6.

Back 16

double temperature = 98.6

Front 17

Declare a variable precise and initialize it to the value 1.09388641.

Back 17

double precise = 1.0938864;

Front 18

Write a single statement that will print the message "first is " followed by the value of first, and then a space, followed by "second = ", followed by the value of second. Print everything on one line and go to a new line after printing. Assume that first has already been declared as a double and that second has been declared as an int . Assume also that the variables have already been given values .

Back 18

System.out.println("first is " + first + " second = " + second + "\n");

Front 19

Back 19

System.out.println(" i = " + i + " f = " + f);

Front 20

Given an int variable datum that has already been declared , write a few statements that read an integer value from standard input into this variable .

Back 20

Scanner input = new Scanner(System.in);

datum = input.nextInt();

Front 21

Write a statement that reads an integer value from standard input into val. Assume that val has already been declared as an int variable . Assume also that stdin is a variable that references a Scanner object associated with standard input.

Back 21

val = stdin.nextInt();

Front 22

Write a statement that reads a floating point value from standard input into temperature. Assume that temperature. has already been declared as an double variable . Assume also that stdin is a variable that references a Scanner object associated with standard input.

Back 22

temperature = stdin.nextDouble();

Front 23

A location in memory used for storing data and given a name in a computer program is called a _____ because _____

Back 23

A variable because the data in the location can be changed.

Front 24

Of the following variable names, which is the best one for keeping track of whether a patient has a fever or not?

Back 24

hasFever

Front 25

Of the following variable names, which is the best one for keeping track of whether an integer might be prime or not?

Back 25

mightBePrime

Front 26

Which is the best identifier for a variable to represent the amount of money your boss pays you each month?

Back 26

monthlyPay

Front 27

Given an integer variable drivingAge that has already been declared , write a statement that assigns the value 17 to drivingAge.

Back 27

drivingAge = 17;

Front 28

Given two integer variables oldRecord and newRecord, write a statement that gives newRecord the same value that oldRecord has.

Back 28

newRecord = oldRecord;

Front 29

Given two integer variables matricAge and gradAge, write a statement that gives gradAge a value that is 4 more than the value of matricAge.

Back 29

gradAge = matricAge + 4;

Front 30

Given two int variables , i and j, which have been declared and initialized , and two other int variables , itemp and jtemp, which have been declared , write some code that swaps the values in i and j by copying their values to itemp and jtemp respectively, and then copying itemp and jtemp to j and i respectively.

Back 30

itemp = i;

jtemp = j;

j = jtemp;

i = itemp;

Front 31

Given three already declared int variables , i, j, and temp, write some code that swaps the values in i and j. Use temp to hold the value of i and then assign j's value to i. The original value of i, which was saved in temp, can now be assigned to j.

Back 31

temp = i;

i = j;

j = temp;

Front 32

Given two int variables , firstPlaceWinner and secondPlaceWinner, write some code that swaps their values . Declare any additional variables as necessary.

Back 32

int swap_me = firstPlaceWinner;

firstPlaceWinner = secondPlaceWinner;

secondPlaceWinner = swap_me;

Front 33

Given two double variables , bestValue and secondBestValue, write some code that swaps their values . Declare any additional variables as necessary.

Back 33

double tempNum;

tempNum = bestValue;

bestValue = secondBestValue;

secondBestValue = tempNum;

Front 34

Four integer variables , pos1, pos2, pos3, pos4 have been declared and initialized . Write the code necessary to "left rotate" their values : for each variable to get the value of the successive variable , with pos4 getting pos1's value .

Back 34

int temp;

temp = pos1;

pos1 = pos2;

pos2 = pos3;

pos3 = pos4;

pos4 = temp;

Front 35

Declare an integer constant , MONTHS_IN_YEAR, whose value is 12.

Back 35

final int MONTHS_IN_YEAR = 12;

Front 36

Declare a constant MONTHS_IN_DECADE, whose value is the value of the constant MONTHS_IN_YEAR (already declared ) multiplied by 10.

Back 36

final int MONTHS_IN_DECADE = MONTHS_IN_YEAR * 10;

Front 37

Declare a short variable named patientsAge.

Back 37

short patientsAge;

Front 38

Declare a long integer variable named grossNationalProduct.

Back 38

long grossNationalProduct;

Front 39

Declare and initialize the following variables :monthOfYear, initialized to the value 11

companyRevenue, initialized to the value 5666777

firstClassTicketPrice, initialized to the value 6000

totalPopulation, initialized to the value 1222333

Back 39

int monthOfYear;

int companyRevenue;

short firstClassTicketPrice;

int totalPopulation;

monthOfYear = 11;

companyRevenue = 5666777;

firstClassTicketPrice = 6000;

totalPopulation = 1222333;

Front 40

Write an expression that computes the sum of two variables verbalScore and mathScore (already declared and assigned values ).

Back 40

verbalScore + mathScore

Front 41

Given the variables taxablePurchases and taxFreePurchases (already declared and assigned values ), write an expression corresponding to the total amount purchased.

Back 41

taxablePurchases + taxFreePurchases

Front 42

Write an expression that computes the difference of the variables endingTime and startingTime.

Back 42

endingTime - startingTime

Front 43

Given the variables fullAdmissionPrice and discountAmount (already declared and assigned values ), write an expression corresponding to the price of a discount admission.

Back 43

fullAdmissionPrice - discountAmount

Front 44

Given the variable pricePerCase, write an expression corresponding to the price of a dozen cases.

Back 44

pricePerCase * 12

Front 45

Given the variables costOfBusRental and maxBusRiders of type int , write an expression corresponding to the cost per rider (assuming the bus is full). (Do not worry about any fractional part of the expression -- let integer arithmetic, with truncation, act here.)

Back 45

costOfBusRental / maxBusRiders

Front 46

Write an expression that computes the remainder of the variable principal when divided by the variable divisor. (Assume both are type int .)

Back 46

principal % divisor

Front 47

A wall has been built with two pieces of sheetrock, a smaller one and a larger one. The length of the smaller one is stored in the variable small. Similarly, the length of the larger one is stored in the variable large. Write a single expression whose value is the length of this wall.

Back 47

small + large

Front 48

Assume that price is an integer variable whose value is the price (in US currency) in cents of an item. Assuming the item is paid for with a minimum amount of change and just single dollars, write an expression for the number of single dollars that would have to be paid.

Back 48

price / 100

Front 49

Assume that price is an integer variable whose value is the price (in US currency) in cents of an item. Assuming the item is paid for with a minimum amount of change and just single dollars, write an expression for the amount of change (in cents) that would have to be paid.

Back 49

price % 100

Front 50

Assume that price is an integer variable whose value is the price (in US currency) in cents of an item. Write a statement that prints the value of price in the form "X dollars and Y cents" on a line by itself. So, if the value of price was 4321, your code would print "43 dollars and 21 cents". If the value was 501 it would print "5 dollars and 1 cents". If the value was 99 your code would print "0 dollars and 99 cents".

Back 50

System.out.println(price/100 + " dollars and " + price%100 + " cents ");

Front 51

Assume that an int variable x that has already been declared , and initialized to a non-negative value .Write an expression whose value is the last (rightmost) digit of x.

Back 51

x % 10

Front 52

You are given two variables , already declared and assigned values , one of type double , named price, containing the price of an order, and the other of type int , named totalNumber, containing the number of orders. Write an expression that calculates the total price for all orders.

Back 52

totalNumber * price

Front 53

Write an expression that computes the sum of two double variables total1 and total2, which have been already declared and assigned values

Back 53

total1 + total2

Front 54

Write an expression that computes the difference of two double variables salesSummer and salesSpring, which have been already declared and assigned values .

Back 54

salesSummer - salesSpring

Front 55

You are given two double variables , already declared and assigned values , named totalWeight, containing the weight of a shipment, and weightOfBox, containing the weight of the box in which a product is shipped. Write an expression that calculates the net weight of the product .

Back 55

totalWeight - weightOfBox

Front 56

Write a literal representing the integer value zero.

Back 56

0

Front 57

Write a literal representing the long integer value twelve billion.

Back 57

12000000000L

Front 58

Write a hexadecimal integer literal representing the value fifteen.

Back 58

0xf

Front 59

Write a floating point literal corresponding to the value zero.

Back 59

0f

Front 60

Write a literal corresponding to the floating point value one-and-a-half.

Back 60

1.5f

Front 61

Write a literal corresponding to the value of the first 6 digits of PI ("three point one four one five nine").

Back 61

3.14159d

Front 62

Write a long integer literal that has the value thirty-seven

Back 62

37L

Front 63

You are given two variables , already declared and assigned values , one of type double , named totalWeight, containing the weight of a shipment, and the other of type int , named quantity, containing the number of items in the shipment. Write an expression that calculates the weight of one item.

Back 63

totalWeight / quantity

Front 64

Write an expression that computes the average of the values 12 and 40.

Back 64

(12 + 40) / 2

Front 65

Write an expression that computes the integer average of the int variables exam1 and exam2 (both declared and assigned values ).

Back 65

(exam1 + exam2) / 2

Front 66

The dimensions (width and length) of room1 have been read into two variables : width1 and length1. The dimensions of room2 have been read into two other variables : width2 and length2. Write a single expression whose value is the total area of the two rooms.

Back 66

(width1 * length1) + (width2 * length2)

Front 67

Each of the walls of a room with square dimensions has been built with two pieces of sheetrock, a smaller one and a larger one. The length of all the smaller ones is the same and is stored in the variable small. Similarly, the length of all the larger ones is the same and is stored in the variable large. Write a single expression whose value is the total area of this room. DO NOT any method invocations.

Back 67

(small + large) * (small + large)

Front 68

Given two integer variables distance and speed, write an expression that divides distance by speed using floating point arithmetic, i.e. a fractional result should be produced.

Back 68

(double) distance / speed

Front 69

Calculate the average (as a double ) of the values contained in the integer variables num1, num2, num3 and assign that average to the double variable avg.

Assume the variables num1, num2, and num3 have been declared and assigned values , and the variable avg declared .

Back 69

avg = (double) (num1 + num2 + num3) / 3;

Front 70

Assume that children is an integer variable containing the number of children in a community and that families is an integer variable containing the number of families in the same community. Write an expression whose value is the average number of children per family.

Back 70

(double) children / families

Front 71

Three classes of school children are selling tickets to the school play. The number of tickets sold by these classes, and the number of children in each of the classes have been read into these variables :tickets1, tickets2, tickets3 and class1, class2, class3. Write an expression for the average number of tickets sold per school child.

Back 71

(double) (tickets1 + tickets2+ tickets3) / (class1 + class2 + class3)

Front 72

In mathematics, the Nth harmonic number is defined to be 1 + 1/2 + 1/3 + 1/4 + ... + 1/N. So, the first harmonic number is 1, the second is 1.5, the third is 1.83333... and so on. Assume that n is an integer variable whose value is some positive integer N. Assume also that hn is a variable whose value is the Nth harmonic number. Write an expression whose value is the (N+1)th harmonic number.

Back 72

hn + 1.0 / (n + 1)

Front 73

Given an integer variable bridgePlayers, write a statement that increases the value of that variable by 4.

Back 73

bridgePlayers += 4;

Front 74

Given an integer variable profits, write a statement that increases the value of that variable by a factor of 10.

Back 74

profits = profits * 10;

Front 75

Given an integer variable strawsOnCamel, write a statement that uses the auto-increment operator to increase the value of that variable by 1.

Back 75

strawsOnCamel++;

Front 76

Given an integer variable timer, write a statement that uses the auto-decrement operator to decrease the value of that variable by 1.

Back 76

timer--;

Front 77

Consider this code: "int v = 20; --v; System.out.println(v++);". What value is printed, what value is v left with?

Back 77

19 is printed, v ends up with 20

Front 78

Consider this code: "int s = 20; int t = s++ + --s;". What are the values of s and t?

Back 78

s is 20 and t is 40