Question

Suppose a, b, and sum are int variables and \(\mathrm{c}\) is a double variable. What value is assigned to each variable after each statement executes? Suppose \(a=3\) \(b=5,\) and \(c=14.1\) sum = a + b + c; ___ ___ ___ ___ c /= a; ___ ___ ___ ___ b += c - a; ___ ___ ___ ___ a *= 2 * b + c;

Short answer

Final values are: \( a = 54.3 \), \( b = 6.7 \), \( c = 4.7 \), \( \text{sum} = 22.1 \).

Step-by-step solution

Initial Values

The initial values of the variables are given as follows:- \( a = 3 \)- \( b = 5 \)- \( c = 14.1 \)

Calculate Sum

The first operation is to evaluate \( \text{sum} = a + b + c \).- Calculate \( \text{sum} = 3 + 5 + 14.1 = 22.1 \).- The values are now: \( a = 3 \), \( b = 5 \), \( c = 14.1 \), \( \text{sum} = 22.1 \).

Divide c by a

Next calculate \( c /= a \) which means \( c = c / a \).- Compute \( c = 14.1 / 3 = 4.7 \).- The values are now: \( a = 3 \), \( b = 5 \), \( c = 4.7 \), \( \text{sum} = 22.1 \).

Calculate b with Updated c

Then, perform the operation \( b += c - a \) which means \( b = b + (c - a) \).- First, evaluate \( c - a = 4.7 - 3 = 1.7 \).- Then, compute \( b = 5 + 1.7 = 6.7 \).- The values are now: \( a = 3 \), \( b = 6.7 \), \( c = 4.7 \), \( \text{sum} = 22.1 \).

Calculate a with New b and c

Finally, perform the operation \( a *= 2 * b + c \) which is \( a = a * (2 * b + c) \).- First, calculate \( 2 * b = 2 * 6.7 = 13.4 \).- Next, add \( c \) to \( 2 * b \): \( 13.4 + 4.7 = 18.1 \).- Compute \( a = 3 * 18.1 = 54.3 \).- Final values are: \( a = 54.3 \), \( b = 6.7 \), \( c = 4.7 \), and \( \text{sum} = 22.1 \).

Key concepts

Variable Assignment

In programming, variable assignment is a fundamental concept that allows us to store data or values to be used in calculations or operations later. When we assign values to variables such as \(a = 3\), \(b = 5\), and \(c = 14.1\), we are telling the computer to reserve memory space for these variables and to use the given values.

Variable assignment is straightforward. The variable you are assigning to is called the 'lvalue,' and the value being assigned is the 'rvalue.' For example, in the statement \(\text{sum} = a + b + c\), we assign the 'rvalue' \(a + b + c\) to the 'lvalue' \(\text{sum}\). This operation stores the result of the arithmetic expression \(22.1\) into the variable \(\text{sum}\).

Understanding variable assignment is crucial as it sets the stage for performing more complex operations and functions in programming. It allows for reuse and organization of data, making the code more readable and manageable.

Data Types

Data types are categories of data that tell the computer how the programmer intends to use the data. Common data types include integers (int), floating-point numbers (float or double), characters, and strings.

- Integers (int) are whole numbers without a fractional part, such as \(3\) and \(5\) in our example. These are used for counting and whole number operations.- Doubles or floats refer to numbers that have a decimal point, such as \(14.1\) in \(c\). These are used for precise calculations and to represent large or small numbers.

Choosing the correct data type for a variable is important because it determines how much memory is allocated for the variable and the kind of operations that can be performed on it. In our example, \(a\) and \(b\) are integers, suitable for simple arithmetic operations, while \(c\) is a double, capable of holding more precise values, allowing for fractional operations.

Type Conversion

Type conversion is the process of converting a variable from one data type to another. This can be implicit or explicit, depending on the programming language and context of the operation.

- Implicit conversion happens automatically when you perform arithmetic operations between different data types. In the expression for \(\text{sum} = a + b + c\), the integer variables \(a\) and \(b\) are implicitly converted to doubles to perform the addition with \(c\), which is already a double.- Explicit conversion, also known as casting, requires you to manually specify the conversion. This might be necessary when you want to convert a double back into an integer or vice versa deliberately.

Type conversion is essential in ensuring that calculations and operations among variables of different types are correctly processed. Be cautious, as converting types can lead to truncation or loss of data, especially when converting from a more precise type, like double, to a less precise type, like int.