如何输出vector中的类的成员和binary_search的位置？

[vccsdn]

#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream>
#include <functional>
#include <string>
using namespace std;

class A
{
public:
int id;
string name;
};

class comp
{
public:
bool operator() (const A& a, const A& b) const
{
return a.id < b.id;
}
};

int main()
{
vector<A> vt;
A a;
for (int i=0; i<10; i++)
{
a.id = i;
a.name = i;
vt.push_back (a);
}
//下面编译不过去，我要输出vt中包含的所有A类的id
//copy (vt.begin(), vt.end(),
// ostream_iterator<A>(cout, "\n"));

A b;
b.id = 3;
bool ret = binary_search(vt.begin(), vt.end(), b, comp()); //我同时想得到检索到的A的name怎么办?
if (ret)
cout << "Found" << endl;
else
cout << "Not Exist" << endl;
}

[zengwujun]

这样子可以输出id

class A
{
public:
int id;
string name;
operator int(){return id;}//加上隐式转换
};

copy (vt.begin(), vt.end(),
ostream_iterator<int>(cout, "\n"));//改为int

[zengwujun]

binary_search返回bool类型，只能表明元素是否存在。

[shine51151]

binary_search返回bool类型，只能表明元素是否存在，无法返回其它类型值
楼主可以自己设计一个函数，用来返回查找到的下表对应的文件名。
#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream>
#include <functional>
#include <string>
using namespace std;

class A
{
public:
int id;
string name;
};

class comp
{
public:
bool operator() (const A& a, const A& b) const
{
return a.id < b.id;
}
};

int Find(vector<A> vt, int id)
{
int index = -1;
for (int i=0; i<vt.size(); i++)
{
if (vt[i].id==id)
{
index = i;
break;
}
}
if (index >= 0)
return index;
else
return -1;


}

int main()
{
vector<A> vt;
A a;
for (int i=0; i<10; i++)
{
a.id = i;
a.name = "name";//最好单独输入文件名，这样不好控制
vt.push_back (a);
}

//下面编译不过去，我要输出vt中包含的所有A类的id
//copy (vt.begin(), vt.end(),
// ostream_iterator<A>(cout, "\n"));

A b;
b.id = 3;
int index = 0;
index = Find(vt,b.id);
if (index >= 0)
{
cout << "Found" << endl;
cout << vt[index].id << " " << vt[index].name << endl;
}
else
cout << "Not Existed" << endl;
//bool ret = binary_search(vt.begin(), vt.end(), b, comp()); //我同时想得到检索到的A的name怎么办?
/*if (ret)
{
cout << "Found" << endl;
}
else
cout << "Not Existed" << endl;
*/
return 0;
}