C++/Function/Optional Arguments
optional arguments: unlimited number of parameters
#include <stdarg.h>
unsigned int min( unsigned int first, ... )
{
int minarg, arg;
va_list argptr; // Pointer to optional arguments
if( first == 0)
return 0;
va_start( argptr, first);
minarg = first;
while( (arg = va_arg(argptr, unsigned int) ) != 0)
if( arg < minarg)
minarg = arg;
va_end (argptr);
return minarg;
}
#include <iostream>
using namespace std;
int main()
{
cout << "The minimum of : 1 2 3 4 5 " << "is:" << min(1,2,3,4,5)
<< endl;
return 0;
}
Using variable-length argument lists
#include <iostream>
#include <iomanip>
#include <stdarg.h>
using namespace std;
double average( int, ... );
int main()
{
double w = 3.5, x = 2.5, y = 1.7, z = 1.2;
cout << setiosflags( ios::fixed | ios::showpoint )
<< setprecision( 1 ) << "w = " << w << "\nx = " << x
<< "\ny = " << y << "\nz = " << z << endl;
cout << setprecision( 3 ) << "\nThe average of w and x is "
<< average( 2, w, x )
<< "\nThe average of w, x, and y is "
<< average( 3, w, x, y )
<< "\nThe average of w, x, y, and z is "
<< average( 4, w, x, y, z ) << endl;
return 0;
}
double average( int i, ... )
{
double total = 0;
va_list ap;
va_start( ap, i );
for ( int j = 1; j <= i; j++ )
total += va_arg( ap, double );
va_end( ap );
return total / i;
}