What is Array in C#

Array is a collection of similar data types. In array we access the value using index.
Declaration of array
Int [ ] marks = new int [5];
Assigning value to the array

1. Marks [0] = 90; Marks[1] = 80;
2. Int [ ] marks = new int [ 5 ] { 2, 3,4,5,6 }
3. Int [ ] marks = { 2, 3, 4,5, 6,7,8}

Retrieving value from Array
int Sum = 0;
For (int i=0; i<= marks. Length; i++)
{
Sum = Sum + marks [i];
}
Response. Write (sum);