Question

Write Java statements to accomplish each of the following tasks: a) Use one statement to assign the sum of \(x\) and \(y\) to \(z,\) then increment \(x\) by 1 b) Test whether variable count is greater than \(10 .\) If it is, print "Count is greater than \(10 "\) c) Use one statement to decrement the variable \(x\) by 1 , then subtract it from variable total and store the result in variable total. d) Calculate the remainder after \(q\) is divided by divisor, and assign the result to q. Write this statement in two different ways.

Short answer

a) z = x + y; x++; b) if(count > 10) System.out.println('Count is greater than 10'); c) x--; total -= x; d) q = q % divisor; or q %= divisor;

Step-by-step solution

Part a) Assign Sum and Increment

First, add x and y and assign the result to z. Then, increment x by 1. This is accomplished by using the compound assignment and increment operators in Java.

Part b) Conditional Testing

Use an if statement to test if count is greater than 10. If the condition is true, use System.out.println to print the specified message.

Part c) Decrement and Subtract

Decrement x by 1 using the decrement operator '--'. After decrementing, subtract the new value of x from total and store it back in total using the '-=' compound assignment operator.

Part d) Calculate Remainder

To find the remainder after dividing q by divisor, you can use the modulus operator '%'. Do this in two statements: One, by using the assignment operator directly, and the other by using the modulus assignment operator '%='.

Key concepts

Assignment Operators in Java

In the realm of Java programming, assignment operators are fundamental tools that enable us to assign values to variables. Commonly, the simple assignment operator '=' is used to assign the value on its right to the operand on its left, like in the statement z = x + y. However, Java takes it up a notch with compound assignment operators that combine an arithmetic operation with an assignment. These include operators like +=, -=, *=, and others.

For instance, in our exercise, we use the += operator to both sum up two numbers and assign the result to a variable in a single concise step. The simple elegance of these operators allows for writing more streamlined and readable code, crucial for efficient Java development. Compound assignment operators do more than just condense your code - they also save precious processing time by reducing the number of operations required.

Increment and Decrement Operators

Java's increment (++) and decrement (--) operators are incredibly handy for manipulating variable values by a unit of one. This may sound trivial, but it's a staple in loop controls and updating counters. Using x++ or ++x will increase the value of x by 1, while x-- or --x will decrease it by 1.

These operators come in two flavors: prefix and postfix. Prefix (++x) increments the value before it's used in an expression, whereas postfix (x++) increments the value after the expression is evaluated. Similarly, prefix decrement (--x) and postfix decrement (x--) work on the same principle but in reverse. Understanding the subtle differences between these can be pivotal in loops and calculations where the order of operations matters.

Conditional Statements

The power of conditional statements lies in their ability to steer the flow of a program based on certain conditions. In Java, the most common conditional statement is the if statement, which executes a block of code only if a specified condition holds true. Conditional statements are like decision-making crossroads that allow a program to react differently to varying scenarios.

In our example, the condition count > 10 is tested using an if statement. If the condition evaluates to true, Java will execute the subsequent block of code, printing out the message. Conditionals are essential for creating dynamic and responsive applications that can handle a variety of inputs and situations. They are the building blocks for more complex control structures such as loops and switch statements.

Modulus Operator

Java's modulus operator (%) is less commonly discussed but just as important. It calculates the remainder of dividing two numbers. For example, 7 % 3 would result in 1 because when 7 is divided by 3, the remainder is 1.

In the exercise provided, the modulus operator is used to find the remainder of q divided by divisor. It's particularly useful in tasks that involve periodic events or need to wrap around a series - think about anything from clock arithmetic to determining even or odd numbers. The operator is also accompanied by its compound form %=, which updates the variable in place. These tools are invaluable for Java programmers, especially in mathematical computations or algorithms where remainders play a critical role.