C++省略参数(va_list va_start va_arg va_end)的简单应用

原文参考自:http://www.cnblogs.com/hanyonglu/archive/2011/05/07/2039916.html

 #include <iostream>
 #include <stdarg.h>
 using namespace std;
 #define COUNT 5

 const char *data[COUNT] =
 {
     "hello",
     "world",
     "java",
     "C#",
     "Python"
 };
 void fun(int a,int b,...)
 {
     cout<<"a="<<a<<endl;
     cout<<"b="<<b<<endl;
     va_list ap;
     va_start(ap,b);
     cout<<"defaut="<<va_arg(ap,char*)<<endl;
     va_end(ap);
 }
 void Dolog(const char *szFileName,const char *fmt,...)
 {
     va_list ap;
     va_start(ap,fmt);
     FILE *fp = fopen(szFileName,"a+");
     if(NULL == fp)
     {
         return;
     }
     vfprintf(fp,fmt,ap);
     va_end(ap);
     fclose(fp);
 }

 int main()
 {
     int a=,b=;
     char str[] = "Hello World";
     fun(a,b,str);
     for(int i=;i<COUNT;i++)
     {
         Dolog("log.txt","%s\n",data[i]);
     }
     system("pause");
     return ;
 }

log.txt内容:

hello
world
java
C#
Python