编写简单的未确定参数的函数.使用了stdarg头文件里的宏。va_list, va_start, va_end, va_arg.

#include <iostream>
#include <string>
#include <cstdarg>

using namespace std;

void myerror(const char* p...);
int main()
{
 int i = 0;
 char *s = "slience";
 char c = 's';
 myerror("%d %s %c %c %s %d", i, s, c, c, s, i);
 cout<<endl;
 printf("%d %s %c %c %s %d", i, s, c, c, s, i);
 cout<<endl;
 system("pause");
 return 0;
}

void myerror(const char* p...)
{
 va_list ap;
 va_start(ap, p);
 //string s = "char*";
 int i = 0;
 while(p[i] != '\0')
 {
  if(p[i] == '%')
  {
   if(p[i + 1] == 'd')
   {
    int num = va_arg(ap, int);
    i = i + 2;
    cout<<num;
   }
   else if(p[i + 1] == 's')
   {
    char* ps = va_arg(ap, char*);
    i = i + 2;
    cout<<ps;
   }
   else if(p[i + 1] == 'c')
   {
                char c = va_arg(ap, char);
    i = i + 2;
    cout<<c;
   }
   else if(p[i + 1] == '%')
   {
                cout<<'%';
   }
   else
   {
    cout<<"I cannot understand %"<<p[i + 1];
    break;
   }
  }
  else
  {
   cout<<p[i];
   i++;
  }
 }
 va_end(ap);
}