property and class variable inside a loop

Question

hello... i have made a class student with a public string variable s1 and a RW property index...

in main method i read into index from the screen and in a loop is in main i check the value of s1, which is sets by index property... in my class student, i have a loop but the context of s1 is empty???!!!  i aprreciate any help... regards

 

class Student{

public string s1;

public string index

{

get{return this.s1;}

set{ this.s1 = value; }

}

if(s1=="y"){...}

else{...}

 

static void Main(string[] args)

{

Student st = new Student();

Console.WriteLine("please choose y or n");

st.index = Console.ReadLine();

if (st.s1 == "y"||st.s1=="n"){....}

else {.....}