JAVA题库——关于java中的方法

目录

一. 单选题

1. (单选题)You should fill in the blank in the following code with　.public class Test {public static void main(String[] args) { System.out.print("The grade is " + getGrade(78.5)); System.out.print("\nThe grade is " + getGrade(59.5));}public static　getGrade(double score) { if (score >= 90.0)return 'A';else if (score >= 80.0) return 'B';else if (score >= 70.0) return 'C';else if (score >= 60.0) return 'D';elsereturn 'F';}}

2. (单选题)Which of the following is the best for generating random integer 0 or 1?

3. (单选题)　 is a simple but incomplete version of a method.

4. (单选题)Analyze the following code.public class Test {public static void main(String[] args) { System.out.println(m(2));}public static int m(int num) { return num;}public static void m(int num) { System.out.println(num);}}

5. (单选题)Arguments to methods always appear within　.

6. (单选题)Given the following methodstatic void nPrint(String message, int n) { while (n > 0) { System.out.print(message);n--;}}What is k after invoking nPrint("A message", k)?int k = 2;nPrint("A message", k);

7. (单选题)What is k after the following block executes?{int k = 2;nPrint( );}System.out.println(k);

8. (单选题)Analyze the following code:public class Test {public static void main(String[] args) { System.out.println(xMethod(5, 500L));}public static int xMethod(int n, long l) { System.out.println("int, long");return n;}public static long xMethod(long n, long l) { System.out.println("long, long");return n;}}

9. (单选题)Suppose your method does not return any value, which of the following keywords can be used as a return type?

10. (单选题)The signature of a method consists of　.

11. (单选题)　 is to implement one method in the structure chart at a time from the top to the bottom.

12. (单选题)You should fill in the blank in the following code with　.public class Test {public static void main(String[] args) { System.out.print("The grade is "); printGrade(78.5);System.out.print("The grade is "); printGrade(59.5);}public static　printGrade(double score) { if (score >= 90.0) {System.out.println('A');}else if (score >= 80.0) { System.out.println('B');}else if (score >= 70.0) { System.out.println('C');}else if (score >= 60.0) { System.out.println('D');}else { System.out.println('F');}}}

14. (单选题)All Java applications must have a method　.

15. (单选题)Analyze the following code.public class Test {public static void main(String[] args) { System.out.println(max(1, 2));}public static double max(int num1, double num2) { System.out.println("max(int, double) is invoked");if (num1 > num2) return num1;elsereturn num2;}public static double max(double num1, int num2) { System.out.println("max(double, int) is invoked");if (num1 > num2) return num1;elsereturn num2;}}

16. (单选题)Each time a method is invoked, the system stores parameters and local variables in an area of memory, known as　, which stores elements in last-in first-out fashion.

17. (单选题)Analyze the following code:class Test {public static void main(String[] args) { System.out.println(xmethod(5));}public static int xmethod(int n, long t) { System.out.println("int");return n;}public static long xmethod(long n) { System.out.println("long");return n;}}

18. (单选题)A variable defined inside a method is referred to as　.

19. (单选题)(char)('a' + Math.random() * ('z' - 'a' + 1)) returns a random character　

20. (单选题)Given the following method, what is the output of the call nPrint('a', 4)?static void nPrint(String message, int n) { while (n > 0) { System.out.print(message);n--;}}

21. (单选题)Which of the following should be defined as a void method?

22. (单选题)(int)('a' + Math.random() * ('z' - 'a' + 1)) returns a random number　.

23. (单选题)Does the method call in the following method cause compile errors?public static void main(String[] args) { Math.pow(2, 4);}

24. (单选题)(int)(Math.random() * (65535 + 1)) returns a random number　.

25. (单选题)Does the return statement in the following method cause compile errors?public static void main(String[] args) { int max = 0;if (max != 0) System.out.println(max); elsereturn;}

二. 多选题

26. (多选题)The client can use a method without knowing how it is implemented. The details of the implementation are encapsulated in the method and hidden from the client who invokes the method. This is known as　.

一. 单选题

1. (单选题)You should fill in the blank in the following code with　.
public class Test {
public static void main(String[] args) { System.out.print("The grade is " + getGrade(78.5)); System.out.print("\nThe grade is " + getGrade(59.5));
}
public static　getGrade(double score) { if (score >= 90.0)
return 'A';
else if (score >= 80.0) return 'B';
else if (score >= 70.0) return 'C';
else if (score >= 60.0) return 'D';
else
return 'F';
}
}

• A. int
• B. double
• C. boolean
• D. char
• E. void

我的答案: D

2. (单选题)Which of the following is the best for generating random integer 0 or 1?

• A. (int)Math.random()
• B. (int)Math.random() + 1
• C. (int)(Math.random() + 0.5)
• D. (int)(Math.random() + 0.2)
• E. (int)(Math.random() + 0.8)

我的答案: C

3. (单选题)　 is a simple but incomplete version of a method.

• A. A stub
• B. A main method
• C. A non-main method
• D. A method developed using top-down approach

我的答案: A

4. (单选题)Analyze the following code.
public class Test {
public static void main(String[] args) { System.out.println(m(2));
}

public static int m(int num) { return num;
}

public static void m(int num) { System.out.println(num);
}
}

• A. The program has a compile error because the two methods m have the same signature.
• B. The program has a compile error because the second m method is defined, but not invoked in the main method.
• C. The program runs and prints 2 once.
• D. The program runs and prints 2 twice.

我的答案: A

5. (单选题)Arguments to methods always appear within　.

• A. brackets
• B. parentheses
• C. curly braces
• D. quotation marks

我的答案: B

6. (单选题)Given the following method
static void nPrint(String message, int n) { while (n > 0) { System.out.print(message);
n--;
}
}

What is k after invoking nPrint("A message", k)?

int k = 2;
nPrint("A message", k);

• A. 0
• B. 1
• C. 2
• D. 3

我的答案: C

7. (单选题)What is k after the following block executes?
{
int k = 2;
nPrint( );
}
System.out.println(k);

• A. 0
• B. 1
• C. 2
• D. k is not defined outside the block. So, the program has a compile error 答案:d k is defined inside the block. Outside the block, k is not defined.
  
  #
  Section 6.10 Case Study: Generating Random Characters

我的答案: A

8. (单选题)Analyze the following code:
public class Test {
public static void main(String[] args) { System.out.println(xMethod(5, 500L));
}

public static int xMethod(int n, long l) { System.out.println("int, long");
return n;
}

public static long xMethod(long n, long l) { System.out.println("long, long");
return n;
}
}

• A. The program displays int, long followed by 5.
• B. The program displays long, long followed by 5.
• C. The program runs fine but displays things other than 5.
• D. The program does not compile because the compiler cannot distinguish which xmethod to invoke.

我的答案: A

9. (单选题)Suppose your method does not return any value, which of the following keywords can be used as a return type?

• A. void
• B. int
• C. double
• D. public
• E. None of the above

我的答案: A

10. (单选题)The signature of a method consists of　.

• A. method name
• B. method name and parameter list
• C. return type, method name, and parameter list
• D. parameter list

我的答案: B

11. (单选题)　 is to implement one method in the structure chart at a time from the top to the bottom.

• A. Bottom-up approach
• B. Top-down approach
• C. Bottom-up and top-down approach
• D. Stepwise refinement

我的答案: B

12. (单选题)You should fill in the blank in the following code with　.
public class Test {
public static void main(String[] args) { System.out.print("The grade is "); printGrade(78.5);

System.out.print("The grade is "); printGrade(59.5);
}

public static　printGrade(double score) { if (score >= 90.0) {
System.out.println('A');
}
else if (score >= 80.0) { System.out.println('B');
}
else if (score >= 70.0) { System.out.println('C');
}
else if (score >= 60.0) { System.out.println('D');
}
else { System.out.println('F');
}
}
}

• A. int
• B. double
• C. boolean
• D. char
• E. void

我的答案: E

13. (单选题)When you invoke a method with a parameter, the value of the argument is passed to the parameter. This is referred to as　.

• A. method invocation
• B. pass by value
• C. pass by reference
• D. pass by name

我的答案: B

14. (单选题)All Java applications must have a method　.

• A. public static Main(String[] args)
• B. public static Main(String args[])
• C. public static void main(String[] args)
• D. public void main(String[] args)
• E. public static main(String[] args)

我的答案: C

15. (单选题)Analyze the following code.
public class Test {
public static void main(String[] args) { System.out.println(max(1, 2));
}
public static double max(int num1, double num2) { System.out.println("max(int, double) is invoked");

if (num1 > num2) return num1;
else
return num2;
}

public static double max(double num1, int num2) { System.out.println("max(double, int) is invoked");

if (num1 > num2) return num1;
else
return num2;
}
}

• A. The program cannot compile because you cannot have the print statement in a non-void method.
• B. The program cannot compile because the compiler cannot determine which max method should be invoked.
• C. The program runs and prints 2 followed by "max(int, double)" is invoked.
• D. The program runs and prints 2 followed by "max(double, int)" is invoked.
• E. The program runs and prints "max(int, double) is invoked" followed by 2.

我的答案: B

16. (单选题)Each time a method is invoked, the system stores parameters and local variables in an area of memory, known as
　, which stores elements in last-in first-out fashion.

• A. a heap
• B. storage area
• C. a stack
• D. an array

我的答案: C

17. (单选题)Analyze the following code:
class Test {
public static void main(String[] args) { System.out.println(xmethod(5));
}

public static int xmethod(int n, long t) { System.out.println("int");
return n;
}

public static long xmethod(long n) { System.out.println("long");
return n;
}
}

• A. The program displays int followed by 5.
• B. The program displays long followed by 5.
• C. The program runs fine but displays things other than 5.
• D. The program does not compile because the compiler cannot distinguish which xmethod to invoke.

我的答案: B

18. (单选题)A variable defined inside a method is referred to as　.

• A. a global variable
• B. a method variable
• C. a block variable
• D. a local variable

我的答案: D

19. (单选题)(char)('a' + Math.random() * ('z' - 'a' + 1)) returns a random character　

• A. between 'a' and 'z'
• B. between 'a' and 'y'
• C. between 'b' and 'z'
• D. between 'b' and 'y'

我的答案: A

20. (单选题)Given the following method, what is the output of the call nPrint('a', 4)?
static void nPrint(String message, int n) { while (n > 0) { System.out.print(message);
n--;
}
}

• A. aaaaa
• B. aaaa
• C. aaa
• D. invalid call

我的答案: D

21. (单选题)Which of the following should be defined as a void method?

• A. Write a method that prints integers from 1 to 100.
• B. Write a method that returns a random integer from 1 to 100.
• C. Write a method that checks whether a number is from 1 to 100.
• D. Write a method that converts an uppercase letter to lowercase.

我的答案: A

22. (单选题)(int)('a' + Math.random() * ('z' - 'a' + 1)) returns a random number　.

• A. between 0 and (int)'z'
• B. between (int)'a' and (int)'z'
• C. between 'a' and 'z'
• D. between 'a' and 'y'

我的答案: B

23. (单选题)Does the method call in the following method cause compile errors?
public static void main(String[] args) { Math.pow(2, 4);
}

• A. Yes
• B. No

我的答案: B

24. (单选题)(int)(Math.random() * (65535 + 1)) returns a random number　.

• A. between 1 and 65536
• B. between 1 and 65535
• C. between 0 and 65535
• D. between 0 and 65536

我的答案: C

25. (单选题)Does the return statement in the following method cause compile errors?
public static void main(String[] args) { int max = 0;
if (max != 0) System.out.println(max); else
return;
}

• A. Yes
• B. No

我的答案: B

二. 多选题

26. (多选题)The client can use a method without knowing how it is implemented. The details of the implementation are encapsulated in the method and hidden from the client who invokes the method. This is known as　.

• A. information hiding
• B. encapsulation
• C. method hiding
• D. simplifying method

我的答案: AB