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05-25-2009, 04:59 PM
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Java Control Statements
Java Control Statements
1) What are operators and what are the various types of operators available in Java? Ans: Operators are special symbols used in expressions. The following are the types of operators: Arithmetic operators, Assignment operators, Increment & Decrement operators, Logical operators, Biwise operators, Comparison/Relational operators and Conditional operators 2) The ++ operator is used for incrementing and the -- operator is used for decrementing. a)True b)False Ans: a. 3) Comparison/Logical operators are used for testing and magnitude. a)True b)False Ans: a. 4) Character literals are stored as unicode characters. a)True b)False Ans: a. 5) What are the Logical operators? Ans: OR(|), AND(&), XOR(^) AND NOT(~). 6) What is the % operator? Ans : % operator is the modulo operator or reminder operator. It returns the reminder of dividing the first operand by second operand. 7) What is the value of 111 % 13? 1. 3 2. 5 3. 7 4. 9 Ans : c. 8) Is &&= a valid operator? Ans : No. 9) Can a double value be cast to a byte? Ans : Yes 10) Can a byte object be cast to a double value ? Ans : No. An object cannot be cast to a primitive value. 11) What are order of precedence and associativity? Ans : Order of precedence the order in which operators are evaluated in expressions. Associativity determines whether an expression is evaluated left-right or right-left. 12) Which Java operator is right associativity? Ans : = operator. 13) What is the difference between prefix and postfix of -- and ++ operators? Ans : The prefix form returns the increment or decrement operation and returns the value of the increment or decrement operation. The postfix form returns the current value of all of the expression and then performs the increment or decrement operation on that value. 14) What is the result of expression 5.45 + "3,2"? 1. The double value 8.6 2. The string ""8.6" 3. The long value 8. 4. The String "5.453.2" Ans : d 15) What are the values of x and y ? x = 5; y = ++x; Ans : x = 6; y = 6 16) What are the values of x and z? x = 5; z = x++; 1) What are the programming constructs? Ans: a) Sequential b) Selection -- if and switch statements c) Iteration -- for loop, while loop and do-while loop 2) class conditional { public static void main(String args[]) { int i = 20; int j = 55; int z = 0; z = i < j ? i : j; // ternary operator System.out.println("The value assigned is " + z); } } What is output of the above program? Ans: The value assigned is 20 3) The switch statement does not require a break. a)True b)False Ans: b. 4) The conditional operator is otherwise known as the ternary operator. a)True b)False Ans: a. 5) The while loop repeats a set of code while the condition is false. a)True b)False Ans: b. 6) The do-while loop repeats a set of code atleast once before the condition is tested. a)True b)False Ans: a. 7) What are difference between break and continue? Ans: The break keyword halts the execution of the current loop and forces control out of the loop. The continue is similar to break, except that instead of halting the execution of the loop, it starts the next iteration. 8) The for loop repeats a set of statements a certain number of times until a condition is matched. a)True b)False Ans: a. 9) Can a for statement loop indefintely? Ans : Yes. 10) What is the difference between while statement and a do statement/ Ans : A while statement checks at the beginning of a loop to see whether the next loop iteration should occur. A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once. Ans : x = 6; z = 5 
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