Introduction to Java Programming-Comprehensive Version (6th Edition)
Review Questions
Section 3.2 boolean Data Type and Operations
| 3.1 | List six comparison operators. |
| 3.2 | Assume that x is 1 , show the result of the following Boolean expressions:
( true ) && ( 3 > 4 ) !(x > ) && (x > ) (x > ) (x < ) (x != ) (x == ) (x >= ) (x < ) (x != 1 ) == !(x == 1 )
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| 3.3 | Write a Boolean expression that evaluates to true if a number stored in variable num is between 1 and 100 . |
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| 3.4 | Write a Boolean expression that evaluates to true if a number stored in variable num is between 1 and 100 or the number is negative. |
| 3.5 | Assume that x and y are int type. Which of the following are correct Java expressions?
x > y > x = y && y x /= y x or y x and y (x != ) (x = )
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| 3.6 | Can the following conversions involving casting be allowed? If so, find the converted result.
boolean b = true ; i = (int)b; int i = 1 ; boolean b = ( boolean )i;
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| 3.7 | Suppose that x is 1. What is x after the evaluation of the following expression?
(x > 1 ) & (x++ > 1 )
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| 3.8 | Suppose that x is 1. What is x after the evaluation of the following expression?
(x > 1 ) && (x++ > 1 )
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| 3.9 | Show the output of the following program:
public class Test { public static void main(String[] args) { char x = 'a' ; char y = 'c' ; System.out.println(++y); System.out.println(y++); System.out.println(x > y); System.out.println(x - y); } }
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Section 3.3 if Statements
| 3.10 | Suppose x = 3 and y = 2 , show the output, if any, of the following code. What is the output if x = 3 and y = 4 ? What is the output if x = 2 and y = 2 ? Draw a flowchart of the following code:
if (x > 2 ) { if (y > 2 ) { int z = x + y; System.out.println( "z is " + z); } } else System.out.println( "x is " + x);
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| 3.11 | Which of the following statements are equivalent? Which ones are correctly indented? |
| 3.12 | Suppose x = 2 and y = 3 , show the output, if any, of the following code. What is the output if x = 3 and y = 2 ? What is the output if x = 3 and y = 3 ? (Hint: please indent the statement correctly first.)
if (x > 2 ) if (y > 2 ) { int z = x + y; System.out.println( "z is " + z); } else System.out.println( "x is " + x);
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| 3.13 | Are the following two statements equivalent? |
| 3.14 | Which of the following is a possible output from invoking Math.random() ?
323.4 , 0.5 , 34 , 1.0 , 0.0 , 0.234
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| 3.15 | How do you generate a random integer i such that How do you generate a random integer i such that 10 How do you generate a random integer i such that 10 |
Section 3.4 switch Statements
| 3.16 | What data types are required for a switch variable? If the keyword break is not used after a case is processed , what is the next statement to be executed? Can you convert a switch statement to an equivalent if statement, or vice versa? What are the advantages of using a switch statement? |
| 3.17 | What is y after the following switch statement is executed?
x = 3 ; y = 3 ; switch (x + 3 ) { case 6 : y = 1 ; default : y += 1 ; }
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| 3.18 | Use a switch statement to rewrite the following if statement and draw the flowchart for the switch statement:
if (a == 1 ) x += 5 ; else if (a == 2 ) x += 10 ; else if (a == 3 ) x += 16 ; else if (a == 4 ) x += 34 ;
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Section 3.5 Conditional Expressions
| 3.19 | Rewrite the following if statement using the conditional operator:
if (count % 10 == ) System.out.print(count + "\n" ); else System.out.print(count + " " );
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Section 3.6 Formatting Console Output and Strings
| 3.20 | What are the specifiers for outputting a boolean value, a character, a decimal integer, a floating-point number, and a string? |
| 3.21 | What is wrong in the following statements?
(a) System.out.printf( "%5d %d" , 1 , 2 , 3 ); (b) System.out.printf( "%5d %f" , 1 ); (c) System.out.printf( "%5d %f" , 1 , 2 );
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| 3.22 | Show the output of the following statements.
(a) System.out.printf( "amount is %f %e\n" , 32.32 , 32.32 ); (b) System.out.printf( "amount is %5.4f %5.4e\n" , 32.32 , 32.32 ); (c) System.out.printf( "%6b\n" , ( 1 > 2 )); (d) System.out.printf( "%6s\n" , "Java" ); (e) System.out.printf( "%-6b%s\n" , ( 1 > 2 ), "Java" ); (f) System.out.printf( "%6b%-s\n" , ( 1 > 2 ), "Java" );
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| 3.23 | How do you create a formatted string? |
Sections 3.7 “3.8
| 3.24 | List the precedence order of the Boolean operators. Evaluate the following expressions:
true true && false true true && false true true & false
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| 3.25 | Show and explain the output of the following code:
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| 3.26 | Assume that int a = 1 and double d = 1.0 , and that each expression is independent. What are the results of the following expressions?
a = (a = 3 ) + a; a = a + (a = 3 ); a += a + (a = 3 ); a = 5 + 5 * 2 % a; a = 4 + 1 + 4 * 5 % (++a + 1 ); d += 1.5 * 3 + (++d); d -= 1.5 * 3 + d++;
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