2.1 | Which of the following identifiers are valid? applet , Applet , a++ , a , 4#R , $4 , #44 , apps |
2.2 | Which of the following are Java keywords? class , public , int , x , y , radius |
2.3 | Translate the following pseudocode into Java code:
What is kilometer after Step 4? |
2.4 | What are the benefits of using constants? Declare an int constant SIZE with value 20 . |
2.5 | 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 = 46 / 9 ; a = 46 % 9 + 4 * 4 - 2 ; a = 45 + 43 % 5 * ( 23 * 3 % 2 ); a %= 3 / a + 3 ; d = 4 + d * d + 4 ; d += 1.5 * 3 + (++a); d -= 1.5 * 3 + a++; |
2.6 | Show the result of the following remainders. 56 % 6 78 % -4 -34 % 5 -34 % -5 5 % 1 1 % 5 |
2.7 | Find the largest and smallest byte , short , int , long , float , and double . Which of these data types requires the least amount of memory? |
2.8 | What is the result of 25 / 4 ? How would you rewrite the expression if you wished the result to be a floating-point number? |
2.9 | Are the following statements correct? If so, show the output. System.out.println( "the output for 25 / 4 is " + 25 / 4 ); System.out.println( "the output for 25 / 4.0 is " + 25 / 4.0 ); |
2.10 | How would you write the following arithmetic expression in Java?
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2.11 | Which of these statements are true?
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2.12 | Which of the following are correct literals for floating-point numbers ? 12.3 , 12.3e+2 , 23.4e2 , -334.4 , 20 , 39F , 40D |
2.13 | Identify and fix the errors in the following code: 1 public class Test { 2 public void main(string[] args) { 3 int i; 4 int k = 100.0 ; 5 int j = i + 1 ; 6 7 System.out.println( "j is " + j + " and 8 k is " + k); 9 } 10 } |
2.14 | Can different types of numeric values be used together in a computation? |
2.15 | What does an explicit conversion from a double to an int do with the fractional part of the double value? Does casting change the variable being cast? |
2.16 | Show the following output: float f = 12.5F ; int i = ( int )f; System.out.println( "f is " + f); System.out.println( "i is " + i); |
2.17 | Use print statements to find out the ASCII code for '1' , 'A' , 'B' , 'a' , 'b' . Use print statements to find out the character for the decimal code 40 , 59 , 79 , 85 , 90 . Use print statements to find out the character for the hexadecimal code 40 , 5A , 71 , 72 , 7A . |
2.18 | Which of the following are correct literals for characters ? '1' , '\u345dE' , '\u3fFa' , '\b' , \t |
2.19 | How do you display characters \ and " ? |
2.20 | Evaluate the following: int i = '1' ; int j = '1' + '2' ; int k = 'a' ; char c = 90 ; |
2.21 | Can the following conversions involving casting be allowed? If so, find the converted result. char c = 'A' ; i = ( int )c; float f = 1000.34f ; int i = ( int )f; double d = 1000.34 ; int i = ( int )d; int i = 97 ; char c = ( char )i; |
2.22 | Show the output of the following statements: System.out.println( "1" + 1 ); System.out.println( '1' + 1 ); System.out.println( "1" + 1 + 1 ); System.out.println( "1" + ( 1 + 1 )); System.out.println( '1' + 1 + 1 ); |
2.23 | Evaluate the following expressions: 1 + "Welcome " + 1 + 1 1 + "Welcome " + ( 1 + 1 ) 1 + "Welcome " + ( '\u0001' + 1 ) 1 + "Welcome " + 'a' + 1 |
2.24 | How do you convert a decimal string into a double value? How do you convert an integer string into an int value? |
2.25 | How do you obtain the current minute using the System.currentTimeMillis() method? |
2.26 | How do you denote a comment line and a comment paragraph? |
2.27 | What are the naming conventions for class names, method names , constants, and variables ? Which of the following items can be a constant, a method, a variable, or a class according to the Java naming conventions? MAX_VALUE, Test, read, readInt |
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2.28 | Reformat the following program according to the programming style and documentation guidelines. Use the next -line brace style. public class Test { // Main method public static void main(String[] args) { /** Print a line */ System.out.println( "2 % 3 = " + 2 % 3 ); } } |
2.29 | Describe syntax errors, runtime errors, and logic errors. |