面向对象编程基础习题与答案.doc

面向对象编程基础习题及答案 Choice Questions (1pt for each question). To add a to b and store result in b, you write (Note: Java is case-sensitive) A. b += a; B. a = b + a; C. b = A + b; D. a += b; To declare a constant PI, you write A. final static PI = 3.14159; B. final float PI = 3.14159; C. static double PI = 3.14159; D. final double PI = 3.14159; To improve readability and maintainability, you should declare _________ instead of using literal values such as 3.14159. A. variables B. methods C. constants D. classes To declare an int variable x with initial value 200, you write A. int x = 200L; B. int x = 200l; C. int x = 200; D. int x = 200.0; To assign a double variable d to an int variable x, you write A. x = (long)d B. x = (int)d; C. x = d; D. x = (float)d; In Java, the word true is ________. A. a Java keyword B. a Boolean literal C. same as value 1 D. same as value 0 Which of the Boolean expressions below has incorrect syntax? A. (true) (3 4) B. !(x 0) (x 0) C. (x 0) || (x 0) D. (x != 0) || (x = 0) Which of the following is the correct expression that evaluates to true if the number x is between 1 and 100 or the number is negative? A. 1 x 100 x 0 B. ((x 100) (x 1)) || (x 0) C. ((x 100) (x 1)) (x 0) D. (1 x 100) || (x 0) Which of the following is the correct expression of character a? A. a B. a C. \000a D. None of the above. Which of the following statement prints smith\exam1\test.txt? A. System.out.println(smith\exam1\test.txt); B. System.out.println(smith\\exam1\\test.txt); C. System.out.println(smith\exam1\test.txt); D. System.out.println(smith\exam1\test.txt); Suppose i is an int type variable. Which of the following statements display the character whose Unicode is stored in variable i? A. System.out.println(i); B. System.out.println((char)i); C. System.out.println((int)i); D. System.out.println(i + ); The Unicode of a is 97. What is the Unicode for c? A. 96 B. 97 C. 98 D. 99 Which of the following is a constant, according to Java naming