#include <stdio.h>
#include <iostream>
#include <string.h>
using namespace std;
// 带格式化参数的strcat宏定义
#define Strcat(x, fmt, ...) sprintf(x, "%s" #fmt, x, __VA_ARGS__)
int main(void)
{
char buf[200];
for(int k = 0; k < 4; k++)
{
memset(buf, 0, sizeof(buf));
for(int i = 0; i < 2; i++)
{
if((k & (i+1)) == (i+1))
{
//sprintf(buf, "%surl=trackID=%d;seq=1;rtptime=0", buf, i);
Strcat(buf, "url=trackID=%d;seq=1;rtptime=0", i);
if(i == 0 && (k & 0x2) == 2)
strcat(buf, ",");
}
}
cout << k << ": [" << buf << "]" << endl;
}
return 0;
}

运行结果：

[zcm@cpp #181]$make
g++ -Wall -Os -DLINUX -o a a.cpp
[zcm@cpp #182]$./a
0: []
1: ["url=trackID=0;seq=1;rtptime=0"]
2: ["url=trackID=1;seq=1;rtptime=0"]
3: ["url=trackID=0;seq=1;rtptime=0","url=trackID=1;seq=1;rtptime=0"]