Java Chapter 3 Test Questions with Verified
Solutions| Latest Update
Write an if statement that displays the message "The number is valid" if the variable speed is
within the range 0 through 200. ✔️✔️if (speed >= 0 && speed <= 200) System.out.println("The
number is valid");
Write an if statement that displays the message "The number is not valid" if the variable speed
is outside the range 0 through 200. ✔️✔️if (speed < 0 || speed > 200) System.out.println("The
number is not valid");
Assume the variable name references a String object. Write an if statement that displays "Do I
know you?" if the String object contains "Timothy". ✔️✔️if (name.equals("Timothy"))
System.out.println("Do I know you?");
Assume the variables name1 and name2 reference two different String objects, containing
different strings. Write code that displays the strings referenced by these variables in
alphabetical order. ✔️✔️if (name1.compareTo(name2) < 0) System.out.println(name1 + " " +
name2); else System.out.println(name2 + " " + name1);
Modify the statement you wrote in response to Checkpoint 3.20 so it performs a case-
insensitive comparison. ✔️✔️if (name.equalsIgnoreCase("Timothy")) System.out.println("Do I
know you?");
if (x > y) z = 1; else z = 20; ✔️✔️z = x > y ? 1 : 20;
if (temp > 45) population = base * 10; else population = base * 2; ✔️✔️population = temp > 45 ?
base * 10 : base * 2;
if (hours > 40) wages *= 1.5; else wages *= 1; ✔️✔️wages = hours > 40 ? wages * 1.5 : wages * 1;
, if (result >= 0) System.out.println("The result is positive."); else System.out.println("The result is
negative."); ✔️✔️System.out.println(result >=0 ? "The result is positive" : "The result is
negative");
Explain what is meant by the phrase "conditionally executed." ✔️✔️Conditionally executed code
is executed only under a condition, such as an expression being true.
Explain why a misplaced semicolon can cause an if statement to operate incorrectly. ✔️✔️The
semicolon indicates the end of a statement. if you end a statement early, or end something that
is not a statement, java will not understand what you are trying to do.
Why is it good advice to indent all the statements inside a set of braces? ✔️✔️By indenting the
conditionally executed statements, you are causing them to stand out visually. This is so you
can tell at a glance what part of the program the if statement executes.
What happens when you compare two String objects with the == operator? ✔️✔️It will only
evaluate it as truer vecause == is used for primitive operators such as boolean, int, and double.
Explain the purpose of a flag variable. Of what data type should a flag variable be? ✔️✔️A flag is
a boolean variable that signals when some condition exists in the program. When the flag
variable is set to false, it indicates the condition does not yet exist. When the flag variable is set
to true, it means the condition does exist.
What risk does a programmer take when not placing a trailing else at the end of an if-else-if
statement? ✔️✔️There is a chance that the program will not compile because Java is looking for
other factors that may be possible. No code executed.
Briefly describe how the && operator works. ✔️✔️It takes two boolean expressions as operands
and creates a boolean expression that is true only when both subexpressions are true
Solutions| Latest Update
Write an if statement that displays the message "The number is valid" if the variable speed is
within the range 0 through 200. ✔️✔️if (speed >= 0 && speed <= 200) System.out.println("The
number is valid");
Write an if statement that displays the message "The number is not valid" if the variable speed
is outside the range 0 through 200. ✔️✔️if (speed < 0 || speed > 200) System.out.println("The
number is not valid");
Assume the variable name references a String object. Write an if statement that displays "Do I
know you?" if the String object contains "Timothy". ✔️✔️if (name.equals("Timothy"))
System.out.println("Do I know you?");
Assume the variables name1 and name2 reference two different String objects, containing
different strings. Write code that displays the strings referenced by these variables in
alphabetical order. ✔️✔️if (name1.compareTo(name2) < 0) System.out.println(name1 + " " +
name2); else System.out.println(name2 + " " + name1);
Modify the statement you wrote in response to Checkpoint 3.20 so it performs a case-
insensitive comparison. ✔️✔️if (name.equalsIgnoreCase("Timothy")) System.out.println("Do I
know you?");
if (x > y) z = 1; else z = 20; ✔️✔️z = x > y ? 1 : 20;
if (temp > 45) population = base * 10; else population = base * 2; ✔️✔️population = temp > 45 ?
base * 10 : base * 2;
if (hours > 40) wages *= 1.5; else wages *= 1; ✔️✔️wages = hours > 40 ? wages * 1.5 : wages * 1;
, if (result >= 0) System.out.println("The result is positive."); else System.out.println("The result is
negative."); ✔️✔️System.out.println(result >=0 ? "The result is positive" : "The result is
negative");
Explain what is meant by the phrase "conditionally executed." ✔️✔️Conditionally executed code
is executed only under a condition, such as an expression being true.
Explain why a misplaced semicolon can cause an if statement to operate incorrectly. ✔️✔️The
semicolon indicates the end of a statement. if you end a statement early, or end something that
is not a statement, java will not understand what you are trying to do.
Why is it good advice to indent all the statements inside a set of braces? ✔️✔️By indenting the
conditionally executed statements, you are causing them to stand out visually. This is so you
can tell at a glance what part of the program the if statement executes.
What happens when you compare two String objects with the == operator? ✔️✔️It will only
evaluate it as truer vecause == is used for primitive operators such as boolean, int, and double.
Explain the purpose of a flag variable. Of what data type should a flag variable be? ✔️✔️A flag is
a boolean variable that signals when some condition exists in the program. When the flag
variable is set to false, it indicates the condition does not yet exist. When the flag variable is set
to true, it means the condition does exist.
What risk does a programmer take when not placing a trailing else at the end of an if-else-if
statement? ✔️✔️There is a chance that the program will not compile because Java is looking for
other factors that may be possible. No code executed.
Briefly describe how the && operator works. ✔️✔️It takes two boolean expressions as operands
and creates a boolean expression that is true only when both subexpressions are true
