Dart double roundToDouble()
Syntax & Examples

double.roundToDouble() method

The `roundToDouble` method in Dart returns the integer double value closest to the given number.

Syntax of double.roundToDouble()

The syntax of double.roundToDouble() method is:

 double roundToDouble()

This roundToDouble() method of double returns the integer double value closest to this.

Return Type

double.roundToDouble() returns value of type double.


✐ Examples

1 Round a decimal number to the nearest integer

In this example,

  1. We create a double variable num with the value 4.2.
  2. We use the roundToDouble() method to round num to the nearest integer as a double value.
  3. We then print the rounded value to standard output.

Dart Program

void main() {
  double num = 4.2;
  double rounded = num.roundToDouble();
  print('Rounded value of $num: $rounded');
}

Output

Rounded value of 4.2: 4

2 Round a decimal number to the nearest integer (upwards)

In this example,

  1. We create a double variable num with the value 4.8.
  2. We use the roundToDouble() method to round num to the nearest integer as a double value.
  3. We then print the rounded value to standard output.

Dart Program

void main() {
  double num = 4.8;
  double rounded = num.roundToDouble();
  print('Rounded value of $num: $rounded');
}

Output

Rounded value of 4.8: 5

3 Round a negative decimal number to the nearest integer

In this example,

  1. We create a double variable num with the value -4.5.
  2. We use the roundToDouble() method to round num to the nearest integer as a double value.
  3. We then print the rounded value to standard output.

Dart Program

void main() {
  double num = -4.5;
  double rounded = num.roundToDouble();
  print('Rounded value of $num: $rounded');
}

Output

Rounded value of -4.5: -5

Summary

In this Dart tutorial, we learned about roundToDouble() method of double: the syntax and few working examples with output and detailed explanation for each example.