Summary: Casting and Ranges of Values

Key Concepts

Type casting is used to convert values from one type to another in Java.
The cast operators (int) and (double) create temporary values converted to a different data type.
Casting a double to an int truncates the decimal portion (does not round).
In expressions with doubles, ints are automatically converted to doubles.
Rounding doubles to the nearest integer: (int)(x + 0.5) for positive numbers, (int)(x - 0.5) for negative numbers.
Integer values in Java (int type) have a finite range from Integer.MIN_VALUE to Integer.MAX_VALUE.
Integer overflow occurs when a value outside the allowed range is assigned to an int, potentially resulting in incorrect values.

Important Formulas

Casting double to int: int result = (int) doubleValue;
Casting int to double: double result = (double) intValue;
Rounding positive double to nearest int: int rounded = (int)(doubleValue + 0.5);
Rounding negative double to nearest int: int rounded = (int)(doubleValue - 0.5);

Common Pitfalls

Forgetting that integer division truncates the result (e.g., 3 / 4 equals 0, not 0.75).
Not considering potential integer overflow when working with large numbers.
Confusing truncation (what happens when casting double to int) with rounding.
Forgetting to cast when necessary, leading to unexpected results in calculations.