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 \(\mathbf{a}=3\) $$\begin{array}{l} b=5, \text { and } c=14.1 & \text { ___ }& \text { ___ }& \text { ___ }& \text { ___ }\\\ \text { sum } =a+b+c & \text { ___ }& \text { ___ }& \text { ___ }& \text { ___ }\\\ c /=a & \text { ___ }& \text { ___ }& \text { ___ }& \text { ___ }\\\ a *=2 * b+c ;& \text { ___ }& \text { ___ }& \text { ___ }& \text { ___ } \\\\\end{array}$$

Short answer

Final values: a = 14, b = 5, c = 4.7, sum = 22.1.

Step-by-step solution

Initial Values

Starting with the initial values, we have- \(a = 3\)- \(b = 5\)- \(c = 14.1\).

Calculate Sum

The sum is calculated by adding \(a\), \(b\), and \(c\):\[\text{sum} = a + b + c = 3 + 5 + 14.1 = 22.1\]After this step, \( \text{sum} = 22.1 \).

Division Operation

The variable \(c\) is divided by \(a\):\[c = \frac{c}{a} = \frac{14.1}{3} = 4.7\]Now, \(c = 4.7\).

Update a with Multiplication and Addition

We update \(a\) using the expression \(a = 2 * b + c\):\[a = 2 * 5 + 4.7 = 10 + 4.7 = 14.7\]\(a\) gets the value \(14.7\). Remembering that \(a\) was an integer and therefore loses precision, the variable will actually be stored as \(a = 14\).

Final Values

After all operations:- \(a = 14\)- \(b = 5\)- \(c = 4.7\)- \(\text{sum} = 22.1\)

Key concepts

Data Types

In C++ programming, data types are essential because they essentially define what kind of data a variable can hold. Each data type consumes a different amount of memory and provides different capabilities:

• int: This is a basic data type used to store integers, like -3, 0, 123. It typically occupies 4 bytes of memory.
• double: This data type is used for storing floating-point numbers, for example, 3.14159 or -0.001. It occupies more memory, usually 8 bytes, but it allows for decimals and fractions.

Data types help the compiler to understand how to process the data the program operates on. They also define the limits of your variables, ensuring you don't store a floating-point number in an int variable. Understanding data types leads to more efficient and error-free code.

Variables

Variables act as containers for storing data values in programming. They have a specific name and data type connected to them, and their values can change while code executes:

• In the exercise, variables like a, b, c, and sum are initialized to hold different values.
• Each of these variables gets assigned a type: int for whole numbers and double for numbers with decimals.

When you create a variable, you decide the name and the type. Using descriptive names makes code easier to read and maintain, while choosing the right data type ensures you can store the correct amount of information.

Arithmetic Operations

Arithmetic operations are the basic operations you can perform on numbers in C++, separated into addition, subtraction, multiplication, and division:

• Addition (+): Combines numbers with each other, like \( a + b + c \).
• Subtraction (-): Calculates the difference between numbers.
• Multiplication (*): Multiplies numbers, important in expressions like \( 2 * b + c \).
• Division (/): Divides one number by another; remember, when dividing integers, the result is an integer too.

Understanding the basic arithmetic operations unlocks the ability to solve mathematical expressions in your code. Always remember that in C++, integer arithmetic differs from floating point. Integer operations round down the result, like in dividing 7 by 2, which equals 3.

Type Casting

Type casting is the conversion of a variable from one data type to another. It's essential for ensuring data types match in operations:

• Explicit type casting is when we manually convert, using syntax like (double)myInt.
• Implicit type casting occurs automatically, such as when a double is assigned to an int variable - causing loss of precision.

In the original exercise, the variable a was supposed to be a float value due to its calculation, but was stored as an integer. This implicit type casting loses detail. Understanding type casting helps prevent unintentional data losses and makes sure you precisely control how data changes types.