Question 1

What does the following statement sequence print? final String str = "Java";
Str += " is powerful";
System.out.println(str);
A) Java is powerful
B) Java + is powerful
C) is powerful
D) Nothing; compile-time error

Accepted Answer

The code will result in a compile-time error because the variable 'str' is declared as 'final', meaning it cannot be reassigned or modified after its initial assignment.

Question 2

What does the following statement sequence print? String str = "Hello";
Int n = str.length();
String mystery = str.substring(0, 1)
+ str.substring(n - 2, n + 1);
System.out.println(mystery);
A) Run-time error
B) He
C) Ho
D) Hry

Accepted Answer

The answer of What does the following statement sequence print?...

Question 3

What does the following statement sequence print? String str = "Java";
Str += " is powerful";
System.out.println(str);
A) Java is powerful
B) Java + is powerful
C) is powerful
D) Compile-time error

Accepted Answer

The += operator concatenates the string on the right to the string on the left. So, the statement str += " is powerful"; concatenates the string " is powerful" to the string str, resulting in the string "Java is powerful".

Question 4

What is the output of this code snippet? double average;
Int grade1 = 87;
Int grade2 = 94;
// System.out.print("The average is " + (grade1 + grade2) / 2.0);
System.out.print("The average is " + average);
A) Compile-time error
B) The average is 91.5
C) The average is 91.5 The average is 91.5
D) The average is 91.5 The average is 0.0

Accepted Answer

The variable 'average' is declared but not initialized, leading to a compile-time error when trying to print it.

Question 5

What is the difference between the result of the following two Java statements?
I. int cents = (int)(100 * price + 0.5);
II. int cents = (100 * price + 0.5);
A) Statement I causes truncation, but II does not
B) Statement II causes truncation, but I does not
C) Statement I compiles, but II does not
D) Statement II compiles, but I does not

Accepted Answer

The answer of What is the difference between the result...

Question 6

What does the following statement sequence print? String str = "Java Is Good";
Int n = str.length();
String mystery = str.substring(n - 4, n) +
Str)charAt(4) + str.substring(0, 4);
System.out.println(mystery);
A) Java
B) Good Java
C) Good
D) Is Good

Accepted Answer

The sequence extracts the last 4 characters "Good", adds the character at index 4 "I", and then adds the first 4 characters "Java", resulting in "GoodIJava".

Question 7

What is the output of the following code snippet?
Int counter = 0;
Counter++;
System.out.print("The initial value of the counter is ");
System.out.println(count);
A) The initial value of the counter is 0
B) The initial value of the counter is 1
C) The code will not compile
D) The initial value of the counter is

Accepted Answer

The code will not compile because of incorrect capitalization of the variable name. "Int" should be "int" and "Counter" should be "counter".

Question 8

What is the output of the following statement sequence? public static void main(String[] args)
{
Int x = 100.0 % 6.0;
System.out.println(x);
}
A) 4
B) Compile-time error
C) Run-time error
D) 16

Accepted Answer

The code will result in a compile-time error because the variable 'x' is declared as an 'Int', which is incorrect syntax in Java. The correct type should be 'int', and also the modulus operation is performed on floating-point numbers, which should be stored in a double or float, not an int.

Question 9

Which statement about number literals in Java is false?
A) Numbers in exponential notation always have type double
B) Zero is an integer
C) Integers must be positive
D) An integer with fractional part of .0 has type double.

Accepted Answer

Integers in Java can be either positive or negative, as well as zero. All other statements are true: numbers in exponential notation always have type double, zero is an integer, and an integer with a fractional part of .0 has type double.

Question 10

Which option represents the best choice for a variable name to represent the average grade of students on an exam?
A) averageGrade
B) $averageGrade
C) avg
D) AveGd

Accepted Answer

"averageGrade" is a clear and easily understandable variable name that accurately represents the data it is storing. It follows common naming conventions, with camelCase capitalization and meaningful words. The other options either include unnecessary symbols or use abbreviations or unclear abbreviations that could make the code harder to read and understand.

Question 11

The typical ranges for integers may seem strange but are derived from
A) Base 10 floating-point precision
B) Field requirements for typical usage and limits
C) Overflows
D) Powers of two because of base 2 representation within the computer

Accepted Answer

The typical ranges for integers are derived from powers of two because of base 2 representation within the computer. Integers in computers are represented using a fixed number of bits, and the maximum value that can be represented is determined by the number of bits used. Since computers use a binary system, the number of bits used is typically a power of two (such as 8, 16, 32, or 64). The range of values that can be represented using a certain number of bits is determined by the number of bits and whether the representation is signed or unsigned.

Question 12

What is result of evaluating the following expression? (45 / 6) % 5
A) 2
B) 7
C) 2.5
D) 3

Accepted Answer

First, divide 45 by 6, which equals 7.5. Then, take the modulus of 7.5 with 5, which results in 2.5. However, since modulus typically deals with integers, the integer part of 7.5 is considered, resulting in 2.

Question 13

Which of the following statements about constants in Java are true?
I. Although not required, constants are commonly named using uppercase letters
II. Only integer values can appear as constants
III. A variable can be defined with an initial value, but the reserved word final prevents it from being changed
IV. A named constant makes computations that use it clearer
A) I, II, III
B) II, III, IV
C) I, III, IV
D) I, II, IV

Accepted Answer

Statement I is true, as it is a common convention to name constants with uppercase letters to distinguish them from variables. 
Statement II is false, as constants can take on values of other data types besides integers. 
Statement III is true, as the keyword final is used to declare a variable as a constant that cannot be changed. 
Statement IV is true, as using a named constant can make code more readable and easier to understand. Therefore, the correct choice is C, as it includes all the true statements.

Question 14

What is the output of this code snippet?
Int sum = 22;
Sum = sum + 2;
System.out.print(sum); // sum = sum + 4;
System.out.print(sum);
A) 2424
B) 2425
C) 2428
D) 2528

Accepted Answer

The variable 'sum' is initialized to 22. The line 'Sum = sum + 2;' does not affect 'sum' because 'Sum' is treated as a different variable due to case sensitivity. The 'System.out.print(sum);' prints the value of 'sum', which remains 22, twice, resulting in the output '2424'.

Question 15

What does the following statement sequence print if the user input is 123? public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
System.out.print("Enter a number ");
Int myInt = in.nextInt();
MyInt += 456;
System.out.println(myInt);
}
A) 579
B) Compile-time error
C) Run-time error
D) 123456

Accepted Answer

The statement sequence takes the user input as an integer, adds 456 to it, and then prints the result. If the user input is 123, the result will be 123 + 456 = 579.

Question 16

The assignment operator
A) denotes mathematical equality
B) places a new value into a variable
C) means the same as the equals sign used in algebra
D) makes it illegal to write a statement like sum = sum + 4;

Accepted Answer

The assignment operator, denoted by the "=" symbol in programming, places a new value into a variable. It does not denote mathematical equality or have the exact same meaning as the equals sign used in algebra, and it does not make it illegal to write a statement like "sum = sum + 4;" which is a common way to update the value of a variable.

Question 17

What does the following statement sequence print? String str = "Harry";
Int n = str.length();
String mystery = str.substring(0, 1) + str.substring(n - 2, n);
System.out.println(mystery);
A) Ha
B) Har
C) Hy
D) Hry

Accepted Answer

The code concatenates the first character "H" (str.substring(0, 1)) with the last two characters "ry" (str.substring(n - 2, n)) of the string "Harry", resulting in "Hry".

Question 18

Which statements about numeric types in Java are true?
I. There is more than one integer type
II. The data type float uses twice the storage of double
III. The numeric range of the Java integer type is related to powers of two
A) I, II
B) I, III
C) II, III
D) I, II, III

Accepted Answer

I - True: There are multiple integer types in Java such as byte, short, int, and long.
II - False: The data type float uses 4 bytes of storage while the double data type uses 8 bytes of storage.
III - True: The range of the Java integer type is from -2^31 to 2^31-1 for int and from -2^63 to 2^63-1 for long. This is related to powers of two because 2^31 and 2^63 are the maximum values that can be represented in 32-bit and 64-bit signed two's complement integers, respectively.

Question 19

What does the following statement sequence print if the user input is 123? public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
System.out.print("Enter a number: ");
String str = in.next();
Str += 456;
System.out.println(str);
}
A) 579
B) Compile-time error
C) Run-time error
D) 123456

Accepted Answer

The code concatenates the string "123" with the integer 456, resulting in the string "123456".

Question 20

Which statement is true?
A) Variables cannot be assigned and declared in the same statement
B) Variable names must contain at least one dollar sign
C) Variable names can be no more than 8 characters long
D) It is incorrect to initialize a string variable with a number

Accepted Answer

The answer of Which statement is true?
A) Variables cannot be...

Quiz 4: Fundamental Data Types

What does the following statement sequence print? final String str = "Java"; Str += " is powerful"; System.out.println(str) ;

What does the following statement sequence print? String str = "Hello"; Int n = str.length() ; String mystery = str.substring(0, 1) + str.substring(n - 2, n + 1) ; System.out.println(mystery) ;

What does the following statement sequence print? String str = "Java"; Str += " is powerful"; System.out.println(str) ;

What is the output of this code snippet? double average; Int grade1 = 87; Int grade2 = 94; // System.out.print("The average is " + (grade1 + grade2) / 2.0) ; System.out.print("The average is " + average) ;

What is the difference between the result of the following two Java statements? I. int cents = (int) (100 * price + 0.5) ; II. int cents = (100 * price + 0.5) ;

What does the following statement sequence print? String str = "Java Is Good"; Int n = str.length() ; String mystery = str.substring(n - 4, n) + Str) charAt(4) + str.substring(0, 4) ; System.out.println(mystery) ;

What is the output of the following code snippet? Int counter = 0; Counter++; System.out.print("The initial value of the counter is ") ; System.out.println(count) ;

What is the output of the following statement sequence? public static void main(String[] args) { Int x = 100.0 % 6.0; System.out.println(x) ; }

Which statement about number literals in Java is false?

Which option represents the best choice for a variable name to represent the average grade of students on an exam?

The typical ranges for integers may seem strange but are derived from

What is result of evaluating the following expression? (45 / 6) % 5

What is the output of this code snippet? Int sum = 22; Sum = sum + 2; System.out.print(sum) ; // sum = sum + 4; System.out.print(sum) ;

What does the following statement sequence print if the user input is 123? public static void main(String[] args) { Scanner in = new Scanner(System.in) ; System.out.print("Enter a number ") ; Int myInt = in.nextInt() ; MyInt += 456; System.out.println(myInt) ; }

The assignment operator

What does the following statement sequence print? String str = "Harry"; Int n = str.length() ; String mystery = str.substring(0, 1) + str.substring(n - 2, n) ; System.out.println(mystery) ;

Which statements about numeric types in Java are true? I. There is more than one integer type II. The data type float uses twice the storage of double III. The numeric range of the Java integer type is related to powers of two

What does the following statement sequence print if the user input is 123? public static void main(String[] args) { Scanner in = new Scanner(System.in) ; System.out.print("Enter a number: ") ; String str = in.next() ; Str += 456; System.out.println(str) ; }

Which statement is true?