Midterm Exam AP (2) PDF

# Copy of Midterm 2 ## AP Computer Science A Test Booklet **1.** In the code segment below, assume that the *int* variable *n* has been properly declared and initialized. The code segment is intended to print a value that is 1 more than twice the value of *n*. ```java /* missing code */ System.ou...

# Copy of Midterm 2 ## AP Computer Science A Test Booklet **1.** In the code segment below, assume that the *int* variable *n* has been properly declared and initialized. The code segment is intended to print a value that is 1 more than twice the value of *n*. ```java /* missing code */ System.out.print(result); ``` Which of the following can be used to replace /* missing code */ so that the code segment works as intended? * I. *int result = n * 2;* *result = result + 1;* * II. *int result = n + 1;* *result = result * 2;* * III. *int result = (n + 1) * 2;* **(A)** I only **(B)** II only **(C)** III only **(D)** I and III **(E)** II and III **2.** Consider the following code segment. ```java int a = 5; int b = 8; int c = 3; System.out.println(a + b / c * 2); ``` What is printed as a result of executing this code? **(A)** 2 **(B)** 6 **(C)** 8 **(D)** 9 **(E)** 14 **3.** Consider the following code segment. ```java String oldStr = "ABCDEF"; String newStr = oldStr.substring(1, 3) + oldStr.substring(4); System.out.println(newStr); ``` What is printed as a result of executing the code segment? **(A)** ABCD **(B)** BCDE **(C)** BCEF **(D)** BCDEF **(E)** ABCDEF **4.** In the code segment below, assume that the *int* variables *a* and *b* have been properly declared and initialized. ```java int c = a; int d = b; c += 3; d--; double num = c; num /= d; ``` Which of the following best describes the behavior of the code segment? **(A)** The code segment stores the value of *(a + 3) / b* in the variable *num*. **(B)** The code segment stores the value of *(a + 3) / (b - 1)* in the variable *num*. **(C)** The code segment stores the value of *(a + 3) / (b - 2)* in the variable *num*. **(D)** The code segment stores the value of *(a + 3) / (1 - b)* in the variable *num*. **(E)** The code segment causes a runtime error in the last line of code because *num* is type *double* and *d* is type *int*. **5.** Consider the following code segment, which is intended to find the average of two positive integers, *x* and *y*. ```java int x; int y; int sum = x + y; double average = (double) ( sum / 2); ``` Which of the following best describes the error, if any, in the code segment? **(A)** There is no error, and the code works as intended. **(B)** 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 even values of *sum*. **(C)** In the expression *(double) (sum / 2)*, the cast to *double* is applied too late, so the average will be greater than the expected result for even values of *sum*. **(D)** 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*. **(E)** In the expression *(double) (sum / 2)*, the cast to *double* is applied too late, so the average will be greater than the expected result for odd values of *sum*. **6.** Consider the following methods, which appear in the same class. ```java public void slope(int x1, int y1, int x2, int y2) { int xChange = x2 - x1; int yChange = y2 - y1; printFraction(yChange, xChange); } public void printFraction(int numerator, int denominator) { System.out.print(numerator + "/" + denominator); } ``` Assume that the method call *slope(1, 2, 5, 10)* appears in a method in the same class. What is printed as a result of the method call? **(A)** 8/4 **(B)** 5/1 **(C)** 4/8 **(D)** 2/1 **(E)** 1/5 **7.** Consider the following method, which is intended to calculate and return the expression $(x+y)^2 \over a-b$ ```java public double calculate(double x, double y, double a, double b) { return /* missing code */; } ``` Which of the following can replace /* missing code */ so that the method works as intended? **(A)** Math.sqrt(x ^ 2, y ^ 2, a - b) **(B)** Math.sqrt((x + y) ^ 2) / Math.abs(a, b) **(C)** Math.sqrt((x + y) ^ 2 / Math.abs(a - b)) **(D)** Math.sqrt(Math.pow(x + y, 2) / Math.abs(a, b)) **(E)** Math.sqrt(Math.pow(x + y, 2) / Math.abs(a - b)) **8.** Consider the following method: ```java public double myMethod(int a, boolean b) { /* implementation not shown */ } ``` Which of the following lines of code, if located in a method in the same class as myMethod, will compile without error? **(A)** int result = myMethod(2, false); **(B)** int result = myMethod(2.5, true); **(C)** double result = myMethod(0, false); **(D)** double result = myMethod(true, 10); **(E)** double result = myMethod(2.5, true); **9.** Consider the following code segment. ```java 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 2 **(B)** 2.0 2 **(C)** 2.0 2.0 **(D)** 2.25 2 **(E)** 2.25 2.0 **10.** Consider the following code segment. ```java double x = (int) (5.5 - 2.5); double y = (int) 5.5 - 2.5; System.out.println(x - y); ``` What is printed as a result of executing the code segment? **(A)** -1.0 **(B)** -0.5 **(C)** 0.0 **(D)** 0.5 **(E)** 1.0 **11.** Consider the following code segment. ```java int w = 1; int x = w / 2; double y = 3; int z = (int) (x + y); ``` Which of the following best describes the results of compiling the code segment? **(A)** The code segment compiles without error. **(B)** The code segment does not compile, because the *int* variable *x* cannot be assigned the result of the operation *w / 2*. **(C)** The code segment does not compile, because the integer value 3 cannot be assigned to the *double* variable *y*. **(D)** The code segment does not compile, because the operands of the addition operator cannot be of different types *int* and *double*. **(E)** The code segment does not compile because the result of the addition operation is of type *double* and cannot be cast to an *int*. **12.** Consider the following code segment. ```java double x = 4.5; int y = (int) x * 2; System.out.print(y); ``` What is printed as a result of executing the code segment? **(A)** 8 **(B)** 8.0 **(C)** 9 **(D)** 9.0 **(E)** 10 **13.** Consider the following code segment, which is intended to simulate a random process. The code is intended to set the value of the variable *event* to exactly one of the values 1, 2, or 3, depending on the probability of an event occurring. The value of *event* should be set to 1 if the probability is 70 percent or less. The value of *event* should be set to 2 if the probability is greater than 70 percent but no more than 80 percent. The value of *event* should be set to 3 if the probability is greater than 80 percent. The variable *randomNumber* is used to simulate the probability of the event occurring. ```java int event = 0; if (randomNumber <= 0.70) { event = 1; } if (randomNumber <= 0.80) { event = 2; } else{ event = 3; } ``` The code does not work as intended. Assume that the variable *randomNumber* has been properly declared and initialized. Which of the following initializations for *randomNumber* will demonstrate that the code segment will not work as intended? **(A)** *randomNumber = 0.70;* **(B)** *randomNumber = 0.80;* **(C)** *randomNumber = 0.85;* **(D)** *randomNumber = 0.90;* **(E)** *randomNumber = 1.00;* **14.** The code segment below is intended to calculate the circumference *c* of a circle with the diameter *d* of 1.5. The circumference of a circle is equal to its diameter times pi. ```java /* missing declarations */ c = pi * d; ``` Which of the following variable declarations are most appropriate to replace /* missing declarations */ in this code segment? **(A)** *int pi = 3.14159;* *int d = 1.5;* *final int c;* **(B)** *final int pi = 3.14159;* *int d = 1.5;* *int c;* **(C)** *final double pi = 3.14159;* *double d = 1.5;* *double c;* **(D)** *double d = 1.5;* *final double c = 0.0;* *final double pi = 3.14159;* **(E)** *final double d = 1.5;* *final double c = 0.0;* **15.** Consider the following code segment. ```java String temp = "comp"; System.out.print(temp.substring(0) + " " + temp.substring(1) + " " + temp.substring(2) + " " + temp.substring(3)); ``` What is printed when the code segment is executed? **(A)** comp **(B)** comp **(C)** comp com co c **(D)** comp omp mp p **(E)** comp comp comp comp **16.** Consider the following code segment. ```java int a = 5; int b = 4; int c = 2; a *= 3; b += a; b /= c; System.out.print(b); ``` What is printed when the code segment is executed? **(A)** 2 **(B)** 4 **(C)** 9 **(D)** 9.5 **(E)** 19 **17.** Consider the following code segment. ```java String str = "CompSci"; int num = str.length(); System.out.println(str.substring(0, 3)); ``` What is the value of *num* when the code segment is executed? **(A)** 3 **(B)** 4 **(C)** 5 **(D)** 6 **(E)** 7 **18.** Consider the following code segment. ```java String str = "0"; str += str + 0 + 8; System.out.println(str); ``` What is printed as a result of executing the code segment? **(A)** 8 **(B)** 08 **(C)** 008 **(D)** 0008 **(E)** Nothing is printed, because numerical values cannot be added to a *String* object. **19.** The following method is intended to return *true* if and only if the parameter *val* is a multiple of 4 but is not a multiple of 100 unless it is also a multiple of 400. The method does not always work correctly. ```java public boolean isLeapYear(int val) { if ((val % 4) == 0) { return true; } else{ return (val % 400) == 0; } } ``` Which of the following method calls will return an incorrect response? **(A)** isLeapYear(1900) **(B)** isLeapYear(1984) **(C)** isLeapYear(2000) **(D)** isLeapYear(2001) **(E)** isLeapYear(2010) **20.** A student has created a *Car* class. The class contains variables to represent the following. * A *String* variable called *color* to represent the color of the car. * An *int* variable called *year* to represent the year the car was made. * A *String* variable called *make* to represent the manufacturer of the car. * A *String* variable called *model* to represent the model of the car. The object *vehicle* will be declared as type *Car*. Which of the following descriptions is accurate? **(A)** An instance of the *vehicle* class is *Car*. **(B)** An instance of the *Car* object is *vehicle*. **(C)** An attribute of the *year* object is *int*. **(D)** An attribute of the *vehicle* object is *color*. **(E)** An attribute of the *Car* instance is *vehicle*. **21.** Consider the code segment below. ```java int a = 1988; int b = 1990; String claim = "that the world's athletes " + "competed in Olympic Games in "; String s = "It is " + true + claim + a + " but " + false + claim + b + "."; System.out.println(s); ``` What, if anything, is printed when the code segment is executed? **(A)** It is trueclaima but falseclaimb. **(B)** It is trueclaim1998 but falseclaim1990. **(C)** It is true that the world's athletes competed in Olympic Games in a but false that the world's athletes competed in Olympic Games in b. **(D)** It is true that the world's athletes competed in Olympic Games in 1988 but false that the world's athletes competed in Olympic Games in 1990. **(E)** Nothing is printed because the code segment does not compile. **22.** 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. ```java /* 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;* **(B)** *int onesDigit = num / 10;* *int tensDigit = num % 10;* **(C)** *int onesDigit = 10 / num;* *int tensDigit = 10 % num;* **(D)** *int onesDigit = num % 100;* *int tensDigit = num / 100;* **(E)** *int onesDigit = num / 100;* * int tensDigit = num % 100;* **23.** Which of the following expressions evaluate to 7 ? * I. 9 + 10 % 12 * II. (9 + 10) % 12 * III. 9 - 2 % 12 **(A)** I only **(B)** II only **(C)** I and III **(D)** II and III **(E)** I, II, and III **24.** Consider the following statement. ```java boolean x = (5 < 8) == (5 == 8); ``` What is the value of *x* after the statement has been executed? **(A)** 3 **(B)** 5 **(C)** 8 **(D)** true **(E)** false **25.** Consider the following Boolean expression in which the *int* variables *x* and *y* have been properly declared and initialized. ```java ( x <= 10 ) == ( y > 25) ``` Which of the following values for *x* and *y* will result in the expression evaluating to *true* ? **(A)** *x = 8 and y = 25* **(B)** *x = 10 and y = 10* **(C)** *x = 10 and y = 30* **(D)** *x = 15 and y = 30* **(E)** *x = 25 and y = 30* **26.** Consider the following class. ```java public class WindTurbine { private double efficiencyRating; public WindTurbine() { efficiencyRating = 0.0; } public WindTurbine(double e) { efficiencyRating = e; } } ``` Which of the following code segments, when placed in a method in a class other than *WindTurbine*, will construct a *WindTurbine* object *wt* with an *efficiencyRating* of 0.25? **(A)** *WindTurbine wt = new WindTurbine(0.25);* **(B)** *WindTurbine wt = 0.25;* **(C)** *WindTurbine wt = new WindTurbine();* *wt = 0.25;* **(D)** *WindTurbine wt = new WindTurbine();* *wt.efficiencyRating = 0.25;* **(E)** *new WindTurbine wt = 0.25;* **27.** Consider the following static method. ```java public static int calculate(int x) { x = x + x; x = x + x; x = x + x; return x; } ``` Which of the following can be usedto replace the body of *calculate* so that the modified version of *calculate* will return the same result as the original version for all *x*? **(A)** *return 3 + x;* **(B)** *return 3 * x;* **(C)** *return 4 * x;* **(D)** *return 6 * x;* **(E)** *return 8 * x;* **28.** Consider the following code segment. ```java System.out.print("Hello System.out.println"); System.out.print("!!!"); ``` What is printed as a result of executing the code segment? **(A)** Hello!!! **(B)** Hello System.out.println!!! **(C)** Hello !!! **(D)** !!! Hello System.out.println **(E)** Nothing is printed because the text "System.out.println" cannot appear inside a print statement. **29.** Consider the following code segment. ```java double firstDouble = 2.5; int firstInt = 30; int secondInt = 5; double secondDouble = firstInt - secondInt / firstDouble + 2.5; ``` What value will be assigned to *secondDouble* when the code segment is executed? **(A)** 5.0 **(B)** 12.5 **(C)** 25.5 **(D)** 29.0 **(E)** 30.5 **30.** Consider the following code segment. ```java num += num; num *= num; ``` Assume that *num* has been previously declared and initialized to contain an integer value. Which of the following best describes the behavior of the code segment? **(A)** The value of *num* is two times its original value. **(B)** The value of *num* is the square its original value. **(C)** The value of *num* is two times the square of its original value. **(D)** The value of *num* is the square of twice its original value. **(E)** It cannot be determined without knowing the initial value of *num*. **31.** Consider the following code segment. ```java System.out.print("One"); // Line 1 System.out.print("Two"); // Line 2 System.out.print("Three"); // Line 3 System.out.print("Four"); // Line 4 ``` The code segment is intended to produce the following output, but does not work as intended. ``` OneTwo ThreeFour ``` Which of the following changes can be made so that the code segment produces the intended output? **(A)** Changing *print* to *println* in line 1 only **(B)** Changing *print* to *println* in line 2 only **(C)** Changing *print* to *println* in line 3 only **(D)** Changing *print* to *println* in lines 2 and 3 only **(E)** Changing *print* to *println* in lines 1, 2, 3, and 4 **32.** Consider the following code segment. ```java int a = 3 + 2 * 3; int b = 4 + 3 / 2; int c = 7 % 4 + 3; double d = a + b + c; ``` What is the value of *d* after the code segment is executed? **(A)** 14.0 **(B)** 18.0 **(C)** 20.0 **(D)** 20.5 **(E)** 26.0 **33.** Consider the following code segment, where *k* and *count* are properly declared and initialized *int* variables. ```java k++; k++; count++; k--; count++; k--; ``` Which of the following best describes the behavior of the code segment? **(A)** The code segment leaves both *k* and *count* unchanged. **(B)** The code segment increases both *k* and *count* by 2. **(C)** The code segment increases *k* by 4 and *count* by 2. **(D)** The code segment leaves *k* unchanged and increases *count* by 2. **(E)** The code segment increases *k* by 2 and leaves *count* unchanged. **34.** Which of the following expressions evaluate to 3.5? * I. (double) 2 / 4 + 3 * II. (double) (2 / 4) + 3 * III. (double) (2 / 4 + 3) **(A)** I only **(B)** III only **(C)** I and II only **(D)** II and III only **(E)** I, II, and III **35.** Consider the following code segment. ```java int x = 5; int y = 6; /* missing code */ z = (x + y) / 2; ``` Which of the following can be used to replace /* missing code */ so that the code segment will compile? * I. *int z = 0;* * II. *int z;* * III. *boolean z = false;* **(A)** I only **(B)** II only **(C)** I and II only **(D)** II and III only **(E)** I, II, and III