Showing how fold operator works in Dart language

dart-fold-1-example.dart

void sum(List<int> list){
  int sum = 0;
  
  // 1. first use a for loop to print the sum
  for(int element in list) {
    sum += element;
  }
  print('sum using for loop is: $sum');
  
  // 2. second use fold to print sum
  int foldSum = 0;
  foldSum = list.fold(0, (foldSum, element) => foldSum + element);
  print('sum using fold() is: $foldSum');
}

void main() {
  final list = [1, 2, 3, 4, 5]; // sum is 15
  
  sum(list);
}