How does the array name in C # change the value of an argument by modifying the parameter's value?

usingSystem;namespaceconsoleapplication1{classProgram {voidFint[] a) {a[0] =1;         //In this way, the value of the argument can be modified, indicating that the value of the element is modified in the original memory by this method } Static voidMain (string[] args) {Program obj=NewProgram (); int[] A =New int[4] {6,7,8,9 };         OBJ.F (a);  for(inti =0;i<a.length; i++) {Console.Write (A[i]+" ");        } console.readline (); }     }}

void f (int[] a)        {            a = new Int[5] {1, 2, 3, 4, 5};         }

OBJ.F (a);
In this case, the value of the parameter can not be modified by fixing the parameter value;
Because the array itself is a reference type, the reference is stored in the stack, and the referenced value is the memory allocated in the heap;
Take this program analysis, the first parameter and the argument all point to the same memory block, but when a = new Int[5] {1, 2, 3, 4, 5}; When this statement is executed, the equivalent of allocating a memory to the parameter in the heap;
It's completely irrelevant at the moment! If you really want to change the value of an argument in this way, you can use this format! As shown below:

void f (ref int[] a)
{a = new Int[5] {1, 2, 3, 4, 5};

}
OBJ.F (ref a);

How does the array name in C # change the value of an argument by modifying the parameter's value?