# 1.5 Casting and Range of Variables

**Suggested Skills:** 2.A, 4.A

**LO 1.5.A** — Develop code to cast primitive values to different primitive types in arithmetic expressions and determine the value that is produced as a result.

* **1.5.A.1** — The casting operators `(int)` and `(double)` can be used to convert from a `double` value to an `int` value (or vice versa).
* **1.5.A.2** — Casting a `double` value to an `int` value causes the digits to the right of the decimal point to be truncated.
* **1.5.A.3** — Some code causes `int` values to be automatically cast (widened) to `double` values.
* **1.5.A.4** — Values of type `double` can be rounded to the nearest integer by `(int)(x + 0.5)` for non-negative numbers or `(int)(x - 0.5)` for negative numbers.

**LO 1.5.B** — Describe conditions when an integer expression evaluates to a value out of range.

* **1.5.B.1** — The constant `Integer.MAX_VALUE` holds the value of the largest possible `int` value. The constant `Integer.MIN_VALUE` holds the value of the smallest possible `int` value.
* **1.5.B.2** — Integer values in Java are represented by values of type `int`, which are stored using a finite amount (4 bytes) of memory. Therefore, an `int` value must be in the range from `Integer.MIN_VALUE` to `Integer.MAX_VALUE` inclusive.
* **1.5.B.3** — If an expression would evaluate to an `int` value outside of the allowed range, an **integer overflow** occurs. The result is an `int` value in the allowed range but not necessarily the value expected.

**LO 1.5.C** — Describe conditions that limit accuracy of expressions.

* **1.5.C.1** — Computers allot a specified amount of memory to store data based on the data type. If an expression would evaluate to a `double` that is more precise than can be stored in the allotted amount of memory, a **round-off error** occurs. The result will be rounded to the representable value. To avoid rounding errors that naturally occur, use `int` values.
  * ❌ **EXCLUSION** — Other special decimal data types that can be used to avoid rounding errors are outside scope.