Dart numbers can be classified as −

• int − Integer of arbitrary size. The int data type is used to represent whole numbers.

• double − 64-bit (double-precision) floating-point numbers, as specified by the IEEE 754 standard. The double data type is used to represent fractional numbers

The num type is inherited by the int and double types. The dart core library allows numerous operations on numeric values.

The syntax for declaring a number is as given below −

int var_name;      // declares an integer variable 
double var_name;   // declares a double variable 

Example

void main() {
   // declare an integer
   int num1 = 10;             
     
   // declare a double value
   double num2 = 10.50;  

   // print the values
   print(num1);
   print(num2);
}

It will produce the following output −

10 
10.5 

Note − The Dart VM will throw an exception if fractional values are assigned to integer variables.

Parsing

The parse() static function allows parsing a string containing numeric literal into a number. The following illustration demonstrates the same −

void main() { 
   print(num.parse(''12'')); 
   print(num.parse(''10.91'')); 
}

12 
10.91

void main() { 
   print(num.parse(''12A'')); 
   print(num.parse(''AAAA'')); 
}

Unhandled exception: 
FormatException: 12A 
#0 num.parse (dart:core/num.dart:446) 
#1 main (file:///D:/Demos/numbers.dart:4:13) 
#2 _startIsolate.<anonymous closure> (dart:isolatepatch/isolate_patch.dart:261) 
#3 _RawReceivePortImpl._handleMessage (dart:isolatepatch/isolate_patch.dart:148)