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> Use this file to discover all available pages before exploring further.
# Dart Division Assignment
The `/=` operator is a compound assignment operator in Dart that performs division and assignment in a single operation. It divides the value of the left operand by the value of the right operand and assigns the resulting floating-point quotient back to the left operand.
```dart theme={"dark"}
a /= b;
```
This syntax is semantically equivalent to:
```dart theme={"dark"}
a = a / b;
```
## Type Constraints and Behavior
In Dart, the standard division operator (`/`) strictly evaluates to a `double`, regardless of whether the operands are integers or floating-point numbers. Because the `/=` operator implicitly relies on `/`, it enforces specific type constraints on the left operand:
1. **Valid Types:** The left operand must be declared as a `double` or the broader `num` type. If a `num` is initially assigned an integer, using `/=` will dynamically change its runtime type to `double`.
2. **Compile-Time Error:** You cannot use the `/=` operator on a variable strictly typed as an `int`. Doing so results in a compile-time error: `A value of type 'double' can't be assigned to a variable of type 'int'`.
## Syntax Visualization
```dart theme={"dark"}
// Valid: Left operand is a double
double a = 20.0;
a /= 4;
print(a); // Output: 5.0
// Valid: Left operand is a num
num b = 10; // Runtime type is int
b /= 2; // Runtime type becomes double
print(b); // Output: 5.0
// Invalid: Left operand is strictly an int
int c = 10;
// c /= 2; // ERROR: A value of type 'double' can't be assigned to a variable of type 'int'.
```
*(Note: If integer division assignment is required, Dart provides the `~/=` operator, which performs truncating division and allows the left operand to remain an `int`.)*
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