C++传递无符号长整数

#include <iostream>
#include <ctime>

using namespace std;
void getSeconds(unsigned long *par);

int main () {
   unsigned long sec;
   getSeconds( &sec );

   // print the actual value
   cout << "Number of seconds :" << sec << endl;

   return 0;
}

void getSeconds(unsigned long *par) {
   // get the current number of seconds
   *par = time( NULL );

   return;
}