The illustration shows a code segment with the lines numbered from 1 through 47 and the annotations are as follows:

"//This is the application file: timedemo.cpp. This program
 //demonstrates hiding the helping functions in an unnamed namespace.
 #include <iostream>"
"#include "dtime.h"" annotated as "If you place the using directives here, then the program behavior will be the same."
 "void readHour(int& theHour);
 int main( )
 {
using namespace std;
using namespace dtimesavitch;
int theHour;"
"readHour(theHour);" annotated as "This is a different function readHour than the one in the
implementation file dtime.cpp (shown in Display 12.7)."
"DigitalTime clock(theHour, 0), oldClock;
oldClock = clock;
clock.advance(15);
if (clock == oldClock)
cout << "Something is wrong.";
cout << "You entered " << oldClock << endl;
cout << "15 minutes later, the time will be "
<< clock; << endl;
clock.advance(2, 15);
cout << "2 hours and 15 minutes after that\n"
<< "the time will be "
<< clock; << endl;
return 0;
}
void readHour(int& theHour)
{
using namespace std;
cout << "Let's play a time game.\n"
<< "Let's pretend the hour has just changed.\n"
<< "You may write midnight as either 0 or 24,\n"
<< "but I will always write it as 0.\n"
<< "Enter the hour as a number (0 to 24): ";
cin >> theHour;
if (theHour == 24)
theHour = 0;
 }"

The block within "void readHour(int& theHour)" is highlighted.