AP Comp Sci Unit 1 Test

A code segment will use variables to represent the age of an animal and whether it is considered a house pet. Which of the following variable declarations is most appropriate for the code segment?

int age; 
boolean pet;

B

what’s missing

int x = 5;
int y = 6;
/* missing code */
z = (x + y) / 2;

int z = 0;

C

A program needs to maintain the following information about data captured by a sensor.

• Whether the sensor is currently active

• The number of items detected by the sensor

• The average time per detection, in seconds

   

Which set of variable declarations is most appropriate for this program?

D

boolean active; int items; double avgTime;

In the following code segment,  x  and  y  are properly declared and initialized  double  variables.

 

y = x;
double z = y + x;
System.out.println(z);

Two times the initial value of  x

In the following code segment,  x  and  y  are properly declared and initialized  int  variables.

 

int z = x;
x = y;
y = z;

Which of the following best describes the behavior of the code segment?

D

It swaps the values of  x  and  y.

The following code segment is intended to interchange the values of the  int  variables  x  and  y.  Assume that  x  and  y  have been properly declared and initialized.

int temp = x; 
/* missing code */

Which of the following can be used to replace  /* missing code */  so that the code segment works as intended?

A

x = y; 
y = temp; 

ng code segment.

 

System.out.print(I do not fear computers. );   // Line 1 
System.out.println(I fear the lack of them.);  // Line 2 
System.out.println(--Isaac Asimov);            // Line 3 

 

The code segment is intended to produce the following output but may not work as intended.

 

I do not fear computers. I fear the lack of them. 
--Isaac Asimov 

Which change, if any, can be made so that the code segment produces the intended output?

C

In lines 1, 2, and 3, the text that appears in parentheses should be enclosed in quotation marks.

Consider the following code segment.

 

int a = 5; 
int b = 8; 
int c = 3; 
System.out.println(a + b / c * 2); 

What is printed as a result of executing the code segment?

D

9

Consider the following code segment, which is intended to print the digits of the two-digit  int  number  num  in reverse order. For example, if  num  has the value  75,  the code segment should print  57.  Assume that  num  has been properly declared and initialized.

 

/* missing code */ 
System.out.print(onesDigit); 
System.out.print(tensDigit);

Which of the following can be used to replace  /* missing code */  so that the code segment works as intended?

A

int onesDigit = num % 10; 
int tensDigit = num / 10;

In the following code segment,  x  and  y  are properly declared and initialized  int  variables whose values are positive. The code segment is intended to print the average of  x  and  y.  For example, if  x  is  10  and  y  is  5,  the code segment is intended to print  7.5.

 

int sum = x + y; 
double average = (double) (sum / 2);
System.out.println(average); 

Which of the following best describes the error, if any, in the code segment?

C

In the expression  (double) (sum / 2),  the cast to  double  is applied too late, so the average will be less than the expected result for odd values of  sum.

Consider the following code segment.

 

double num = 9 / 4;
System.out.print(num);
System.out.print(" ");
System.out.print((int) num);

What is printed as a result of executing the code segment?

A

2.0 2

The following code segment is intended to round  val  to the nearest integer and print the result.

 

double val = -0.7; 
int roundedVal = (int) (val + 0.5); 
System.out.println(roundedVal); 

Which of the following best describes the behavior of the code segment?

D

The code segment does not work as intended because the expression  (int) (val + 0.5)  rounds to the nearest integer only when  val  is positive.

Consider the following code segment.

 

int a = 5; 
int b = 4; 
int c = 2; 
a *= 3; 
b += a; 
b /= c; 
System.out.print(b); 

What is printed as a result of executing the code segment?

B

9

Consider the following code segment.

 

int x = 5; 
x += 6 * 2; 
x -= 3 / 2; 

What is the value of  x  after the code segment is executed?

D

16

Consider the following code segment.

 

int a = 4; 
int b = 5; 
a++; 
b++; 
int c = a + b; 
a -= 1; 
System.out.println(a + c); 

What is printed as a result of executing the code segment?

D

15

A PetOwner object is an attribute of a Cat object

B)

The color and size variables are attributes of the poloShirt object.

A)

Attribute:

• title

Behavior:

• play()

A)

Print your name

System.out.println("John Doe");

Print the numbers 1–10

for (int i = 1; i <= 10; i++) {

System.out.println(i)

Find the larger of 15 and 22.

int a = 15; int b = 22;

if (a > b) {

System.out.println(a);

} else {

System.out.println(b); }

Compute the sum of 8 and 17

int a = 8; int b = 17;

2

int sum = a + b;

System.out.println(sum);

Find the area of a rectangle (length × width)

int length = 8;

int width = 5;

int area = length * width;

System.out.println(area);