import java.util.Scanner;
public class test1 {
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
int i=sc.nextInt(); //输入有几组测试数据
for(int j=0;j<i;j++){
int A=sc.nextInt(); //0
int B=sc.nextInt(); //1
int N=sc.nextInt();
int t=A^B; //2
N%=3; //找规律
if(N==0)System.out.println(A);
else if(N==1)System.out.println(B);
else if(N==2)System.out.println(t);
}
}
}