Chapter 5(Java)
What is the output of the following? for (double sample = 2; sample >0; sample = sample -0.5) System.out.print(sample + " ");
Sample 2.0 Sample 1.5 Sample 1.0 Sample 0.5
What is the output produced by the following code? char letter = 'B'; switch (letter) { case 'A': case 'a': System.out.println("Some kind of A."); case 'B': case 'b': System.out.println("Some kind of B."); break; default: System.out.println("Something else."); break; }
Some kind of B
true
True/False: An expression containing the || operator is true if either or both of its operands is true
true
True/False: Class Math is defined in java.lang and does not require an import statement to be used by a program.
true
True/False: Listing cases consecutively with no statements between them enables the cases to perform the same set of statements.
false
True/False: The break statement is required in the last case of a switch selection statement.
true
True/False: The comma (,) formatting flag in a format specifier (e.g., %, 20.2f) indicates that a value should be output with a thousands separator
false
True/False: The default case is required in the switch selection statement.
false
True/False: The expression ((x > y) && (a < b)) is true if either (x > y) is true OR (a < b) is true.
double result = Math.pow(2. 5, 3 );
Write a statement: Calculate the value of 2.5 raised to the power of 3, using the 'pow' method
for (i=1;i<= 20; i++ ) { System.out.print( i ); if (i% 5 == 0 ) System.out.println(); else System.out.print( '\ t' ); }
Write a statement: Print the integers from 1 to 20, using a for loop and the counter variable i. Assume that i has already been declared, but not initialized. Print only 5 integers per line.
i=1; while (i<= 20 ) { System.out.print( i ); if (i% 5== 0 ) System.out.println(); else System.out.print( '\ t' ); ++i; }
Write a statement: Print the integers from 1 to 20, using a while loop and the counter variable i. Assume that i has already been declared, but not initialized. Print only 5 integers per line.
false
True/False: To test for a range of values in a switch statement, use a hyphen (-) between the start and the end values of the range in a case label.
true
True/False: in a do....while statement the brackets ({ }) are used after the 'do' keyword and before the 'while' keyword, then the conditional statement is added after the 'while' keyword, followed by a (;).
for
Typically, ___________statements are used for counter-controlled repetition and while statements for sentinel-controlled repetition
while
Typically, for statements are used for counter-controlled repetition and __________ statements for sentinel-controlled repetition
sum =0; for ( count =1; count <=99; count +=2 ) sum += count;
Write a statement: Sum the odd integers between 1 and 99, using a for statement. Assume that the integer variables sum and count have been declared.
scope
where in a program a variable can be utelized
What is the output produced by the following? int n = -42; do { System.out.println(n); n=n-3; } while (n>0);
-42 A do while always executes once regardless of whether the conditions are met.
If...else construct Vs Switch...case construct
Any kind of relation can be checked in any condition of the If...else construct. The condition can include any relational operator(<,>, <=,>=,==,!=). The Switch...case construct checks only for equality.
If...else construct Vs Switch...case construct
Float values/variables can be used in the boolean expressions of If construct. Float variable cannot be used as in control expression of switch construct. The controlling expression for a switch statement must be one of the types - char,int,short,byte,orString.
Suppose variable1 and variable2 are two variables that have been give values. How do you test whether they are equal when the variables are of type int? How do you test whether they are equal when the variables are of type String?
For int: variable1 == variable 2; For string: variable1.equals(variable2);
false
If the loop-continuation condition in a for header is initially __________ the program does not execute the for statement's body.
What is the output produced by the following code? int key = 1; switch (key + 1) { case 1: System.out.println("Apples"); break; case 2: System.out.println("Oranges"); break; case 3: System.out.println("Peaches"); case 4: System.out.println("Plumbs"); break; default: System.out.println("Fruitless"); }
Oranges
static
Methods that perform common tasks and do not require objects are called _________ methods.
Does the following sequence produce a division by zero? int j = -1; if ((j>0) && (1/(j+1) > 10)) System.out.println(i);
No, it calculated (j>0) and because that is false it short circuits
Can the values true and false be numbers (0 or 1) in Java ?
No. In Java, the values true and false are not numbers, nor can they be type cast to any numeric type. Similarly, values of type int cannot be type cast to boolean values.
switch
The _________ statement selects among multiple actions based on the possible values of an integer variable or expression.
&&
The __________ operator can be used to ensure that two conditions are both true before choosing a certain path of execution.
continue
The __________ statement, when executed in a repetition statement, skips the remaining statements in the loop body and proceeds with the next iteration of the loop.
Break statement in switch...case construct
The break keyword causes the entire switch statement to exit, and the control is passed to statement following the switch...case construct. Without break, the execution just continues to the next case. case 'A': case 'a': System.out.println("Excellent. You need not take the final."); break; Because the first case has no break statement, the effect is the same as having two labels for one case. The break statement is optional in the switch...case construct.
after
The do... while statement tests the loop-continuation condition __________ executing the loop's body; therefore, the body always executes at least once.
structured programming
The use of only Sequence, Selection and/or Repetition statements in programming.
default case in switch...case construct
This keyword gives the switch...case construct a way to take an action if the value of the switch variable does not match with any of the case constants. The default case is optional in the switch...case construct. The default case need not be the last case in aswitch statement, but making it the last case, makes the code clearer.
switch statement (multiple-selection)
a selection statement that is controlled with an integer based expression and uses case declarations to execute programming statements.
increment statement
a statement that increments or decrements a control variable in a loop
constant variable
a variable containing a value which does not change for the entire program.
For each of the following situation, tell which type of loop (while, do-while, and for) would work best: a. Summing a series, such as 1/2 + 1/3 + 1/4 + 1/5 +...+1/10. b. Reading in the list of exam scores for one student. c. Reading in the number of days of sick leave taken by employees in a department.
a. loop b. while c. while
hasNext()
boolean value method used with Scanner to determine if all data has been input
off-by-one error
common programming error where a control statement uses the '<' or '>' operator when it needed the '<=' or '>=' operator.
statement header (for)
first line of a for statement. It includes initialized control variable, loop-continuation condition, and increment of control variable..
%b
formatter used to display a boolean expressions value in a formatted output statement.
Write a multiway if-else statement that classifies the value of an int variable n into one of the following categories and writes out an appropriate message: n<0 or 0≤n<100 or n≥100 Hint: Remember that Boolean expressions are checked in order
if (n<0) System.out.println("n<0"); else if(n<100) System.out.println("0≤n<100"); else System.out.println("n≥100");
end-of-file indicator
system-dependent keystroke combination which the user enter's to indicate that there is no more data to input
