以下程序将打印什么字符串输出?

#define MESG "this is a test" 

#include <stdio.h> 

int main(voID) { 
   int n = 0; 

   while ( n < 5 ) 
      printf("%s\n", MESG); 
      n++; 
   printf("That's all.\n"); 
   return 0; 
}