The factorial of a number is the product of all the integers from 1 to that number.

For example, the factorial of 5 (denoted as 6!) is

1*2*3*4*5 = 120. 

Factorial is not defined for negative numbers and the factorial of zero is one, 0! = 1 

 

Factorial Example with Dart For Loop

void main() {
  var num = 5;
  var factorial = 1;

  for( var i = num ; i >= 1; i-- ) {
    factorial *= i ;
  }
  print(factorial);
}

 

Output

120