In this post, let’s learn how to convert or cast a double to an int and vice versa.

1. Convert double to int

To convert a double to int in Dart, we can use one of the built-in methods depending on your need:

toInt( ) or truncate( ): these 2 methods are equivalent, they both truncate the fractional/decimal part and return the integer part.

round( ): return the closest/nearest integer.

ceil( ): return the least integer that is not smaller than this number.

floor( ): return the greatest integer not greater than this number.

void main() {
  double d = 10.3;

  print(d.toInt());     // 10
  print(d.truncate());  // 10
  print(d.round());     // 10
  print(d.ceil());      // 11
  print(d.floor());     // 10
}

2. Convert int to double

So far, I know 2 ways to convert an integer to a double in Dart:

toDouble( ): as its name is saying, just convert the integer to a double

double.tryParse( ): provide an integer as a String to this method

void main() {
  int i = 5;
  print(i.toDouble());          // 5.0
  print(double.tryParse('$i')); // 5.0
}

Phuc Tran

Creator of Coflutter.

Founder & CTO at Bumbii Technology

Founder at Bumbii K12

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