Question

I have Collection List<Car>.

How to compare each item from this collection with rest without repeatition.

Ex:

1. iteration:

this car is Audi and secondCar is BMW

bool IsSimilar(Car secondCar)
{
  if(this.Name==secondCar.Name) return true;
  return false;
}

this is not permitted:

n iteration

this car is BMW and secondCar is Audi

bool IsSimilar(Car secondCar)
{
  if(this.Name==secondCar.Name) return true;
  return false;
}

Clearer:

List<Car> car=new List<Car>();
List<Pair> pairs=new List<Pair>();
pairs.Cars=new List<Car>();

foreach(Car car in cars)
{
  foreach(Car secondCar in cars)
  {
    if(secondCar!=car)
    {
      if(car.Name==secondCar.name && car.Owner==secondCar.Owner)
      {
        Pair pair=new Pair();
        pair.Cars.Add(car);
        pair.Cars.Add(secondCar);
        pairs.Add(pair);
      }
    }
  }
}

I’m just don’t want to compare cars twice(you know first iteration compare car 1 with car2, next car2 is base car and car1 is secondCar)

Sorry for my terrible English

Answer 1

Don’t loop over the collection, loop over the indices

for (i = 0; i < length(cars); i++) {
    for (j = i+1; j < length(cars); j++) {
        <do comparison>
    }
}