C++ break语句

#include <iostream>

using namespace std;

int main () {
   // Local variable declaration:
   int a = 10;

   // do loop execution
   do {
      cout << "value of a: " << a << endl;
      a = a + 1;
      if( a > 15) {
         // terminate the loop
         break;
      }
   } while( a < 20 );

   return 0;
}