以下C＃代码中的“ -1”是什么意思？

Question

Hey guys I'm just starting to learn C# and I was wondering what the "-1" in the for loop meant?

string[] fruit = { "Apples", "Oranges", "Grapes" };
for (int i = fruit.Length - 1; i >= 0; i--)
{
    // Code Here
    Console.WriteLine(fruit[i]);
}

I was trying to figure out how to go backwards in an array and I was able to do it, but I just want to know how the "-1" works in the for loop. Why is it necessary?

Answer 1

Arrays in C# are 0-indexed, meaning they begin at element [0]. Thus, the largest accessible index is Length-1.

Answer 2

Length of array - 1 is to normalize it. Array starts at 0, while obviously counting numbers starts at 1. So the length of the array (or collection, semantics) - 1 would be the way to access the current index of the collection.

Answer 3

An array starts indexing at 0 to array.length - 1 always and array length is going from 1 2 3..... to array.length, wich means fruit[0] fruit[1]....fruit[fruit.length -1] and that is the last element. So you are starting a reverse loop, from fruit[fruit.length - 1]...... to fruit[0], if you put fruit[fruit.length] you will get indexOutOfBoundsException. Debugging your app is the best way to see what's happening.