translate this into c#

// Code to implement printing out of the twelfth day of Christmas

// This one uses switch and case

#include

#include

using namespace std;

int main () {

int n;

string s1 = "On the ";

string s2 = " day of Christmas, my true love sent to me ";

string s;

string days[4] = {"", "first", "second", "third"};

string x[4] = {"", "A partridge in a pear tree. ", "Two turtle doves, ", "Three French hens, "};

for (int i = 1; i <= 3; i ++)

{

// For each i, print the ith day

s += s1 + days[i] + s2;

for (int j = i; j >= 1; j --)

s += x[j];

}

cout << s << endl;

}