b. Suppose you enter input from the console, when you run the program. What is the output?

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1 Part I. Show the printout of the following code: (write the printout next to each println statement if the println statement is executed in the program). a. Show the output of the following code: public class Test { public static void main(string[] args) { System.out.println(5 % 4); System.out.println(5 / 4); System.out.println(5 + 4 * ); System.out.println((5 + 4) * ); int x = 1; x++; System.out.println(x); x -= 4; System.out.println(x); b. Suppose you enter input 3 6 from the console, when you run the program. What is the output? public class Test { public static void main(string[] args) { java.util.scanner input = new java.util.scanner(system.in); double x = input.nextdouble(); double y = input.nextdouble(); double z = input.nextdouble(); System.out.println("(x < y && y < z) is " + (x < y && y < z)); System.out.println("(x < y y < z) is " + (x < y y < z)); System.out.println("!(x < y) is " +!(x < y)); System.out.println("(x + y < z) is " + (x + y < z)); System.out.println("(x + y < z) is " + (x + y < z)); Part II: (10 pts each): 1 (Using the &&, and operators) Write a program that prompts the user to enter an integer and determines whether it is divisible by 5 and 6, or whether it is divisible by 5 or 6h. Here is a sample run of this program: <Output> Enter an integer: 10 Is 10 divisible by 5 and 6? false Is 10 divisible by 5 or 6? true <End Output> 1

2 (Algebra: solving quadratic equations) The two roots of a quadratic equation ax + bx + c = 0 can be obtained using the following formula: b + b 4ac r1 = and a r b = b 4ac a b 4ac is called the discriminant of the quadratic equation. If it is positive, the equation has two real roots. If it is zero, the equation has one root. If it is negative, the equation has no real roots. Write a program that prompts the user to enter values for a, b, and c, and displays the result based on the discriminant. If the discriminant is positive, display two roots. If the discriminant is 0, display one root. Otherwise, display The equation has no real roots. Note you can use Math.pow(x, 0.5) to compute x. Here is a sample run. <Output> Enter a, b, c: The roots are and <End Output> <Output> Enter a, b, c: The root is -1 <End Output> <Output> Enter a, b, c: 1 3 The equation has no real roots <End Output>

3 Part III: Multiple Choice Questions. 1. The not equal comparison operator in Java is. a.!= = b. ^= c. <> d.!= (the following question will not be covered in exam 1). Which of the following are valid specifiers for the printf statement? a. %10.e b. %4c c. %8.d d. %10b e. %6d 3. What is the printout of the following switch statement? char ch = 'b'; switch (ch) { case 'a': case 'b': case 'c': case 'd': a. abcd b. bb c. bcd d. b e. bbb 4. What is == 3.0? a. true b. There is no guarantee that == 3.0 is true. c. false 3

4 5. What is the output of the following code: (Please indent the statement correctly first.) int x = 9; int y = 8; int z = 7; if (x > 9) if (y > 8) System.out.println("x > 9 and y > 8"); else if (z >= 7) System.out.println("x <= 9 and z >= 7"); else System.out.println("x <= 9 and z < 7"); a. x > 9 and y > 8; b. x <= 9 and z >= 7; c. none d. x <= 9 and z < 7; 6. The default case must be specified in a switch statement. a. true b. false 7. Suppose x is 1. What is x after x +=? a. b. 0 c. 3 d. 4 e Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to. a. 66 b. Illegal expression c. B d. A1 9. Which of the following is a valid identifier? a. 8+9 b. class 4

5 c. $343 d. radius e. 9X Key:cd 10. To add a to b and store result in b, you write (Note: Java is case-sensitive) a. b = A + b; b. b += a; c. a += b; d. a = b + a; 11. Programming style is important, because. a. good programming style helps reduce programming errors b. good programming style can make a program run faster c. a program may not compile if it has a bad style d. good programming style makes a program more readable 1. According to Java naming convention, which of the following names can be variables? a. totallength b. TOTAL_LENGTH c. class d. findarea e. FindArea 13. Which of the following assignment statements is correct to assign character 5 to c? a. char c = 5; b. char c = "5"; c. char c = '5'; d. char c = "344"; Solution: Part III Key: 1. The not equal comparison operator in Java is. a.!= = b. ^= c. <> 5

6 d.!= Key:d. Which of the following are valid specifiers for the printf statement? a. %10.e b. %4c c. %8.d d. %10b e. %6d Key:abde 3. What is the printout of the following switch statement? char ch = 'b'; switch (ch) { case 'a': case 'b': case 'c': case 'd': a. abcd b. bb c. bcd d. b e. bbb Key:e 4. What is == 3.0? a. true b. There is no guarantee that == 3.0 is true. c. false Key:b 6

7 5. What is the output of the following code: (Please indent the statement correctly first.) int x = 9; int y = 8; int z = 7; if (x > 9) if (y > 8) System.out.println("x > 9 and y > 8"); else if (z >= 7) System.out.println("x <= 9 and z >= 7"); else System.out.println("x <= 9 and z < 7"); a. x > 9 and y > 8; b. x <= 9 and z >= 7; c. none d. x <= 9 and z < 7; Key:c 6. The default case must be specified in a switch statement. a. true b. false Key:b 1. Suppose x is 1. What is x after x +=? a. b. 0 c. 3 d. 4 e. 1 Key:c. Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to. a. 66 b. Illegal expression c. B 7

8 d. A1 Key:a 3. Which of the following is a valid identifier? a. 8+9 b. class c. $343 d. radius e. 9X Key:cd 4. To add a to b and store result in b, you write (Note: Java is case-sensitive) a. b = A + b; b. b += a; c. a += b; d. a = b + a; Key:b 5. Programming style is important, because. a. good programming style helps reduce programming errors b. good programming style can make a program run faster c. a program may not compile if it has a bad style d. good programming style makes a program more readable Key:ad 6. According to Java naming convention, which of the following names can be variables? a. totallength b. TOTAL_LENGTH c. class d. findarea e. FindArea Key:ad 7. Which of the following assignment statements is correct to assign character 5 to c? 8

9 a. char c = 5; b. char c = "5"; c. char c = '5'; d. char c = "344"; Key:c 9