C++省略参数(va_list va_start va_arg va

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

 1 #include <iostream>
 2 #include <stdarg.h>
 3 using namespace std;
 4 #define COUNT 5
 5 
 6 const char *data[COUNT] = 
 7 {
 8     "hello",
 9     "world",
10     "java",
11     "C#",
12     "Python"
13 };
14 void fun(int a,int b,...)
15 {
16     cout<<"a="<<a<<endl;
17     cout<<"b="<<b<<endl;
18     va_list ap;
19     va_start(ap,b);
20     cout<<"defaut="<<va_arg(ap,char*)<<endl;
21     va_end(ap);
22 }
23 void Dolog(const char *szFileName,const char *fmt,...)
24 {
25     va_list ap;
26     va_start(ap,fmt);
27     FILE *fp = fopen(szFileName,"a+");
28     if(NULL == fp)
29     {
30         return;
31     }
32     vfprintf(fp,fmt,ap);
33     va_end(ap);
34     fclose(fp);
35 }
36 
37 int main()
38 {
39     int a=1,b=2;
40     char str[] = "Hello World";
41     fun(a,b,str);
42     for(int i=0;i<COUNT;i++)
43     {
44         Dolog("log.txt","%s
",data[i]);
45     }
46     system("pause");
47     return 0;
48 }

View Code

log.txt内容:

hello
world
java
C#
Python