How to use the import keyword in Dart

Overview

In Dart, we use the import keyword to import libraries or other files within a program.

Syntax

import library_name;

Assume we need some mathematical constant such as pi or a function like sqrt() in our program, then we have to import the dart: math.

Code

The following code shows how to use the import keyword in Dart.

// import keyword in dart
import 'dart:math'; 
void main() { 
  var radius = 4;
  var cir = 2 *pi * radius;
  print("The circumference of a circle: $cir");
  // using sqrt() to find square root of 81 
  print("The square root of 81 is: ${sqrt(81)}"); 
}

Explanation

  • Line 2: We import the dart: math library to access the pi and the sqrt() function.
  • Line 3: We create a main() function.
  • Line 4: We declare a variable named radius and assign a value to it.
  • Line 5: We declare a variable named cir which holds the value from the computation.
  • Line 6: We display the result using print().
  • Line 8: We calculate the square root of 81 using the sqrt() function from the dart:math library. Finally, we display the result.

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