帮忙看看这个程序#include iostream#include vector#include algorithm#include iteratorusing na
帮忙看看这个程序
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
template <class ForwardIterator, class T>
void iota_n(ForwardIterator first, int n,T value)
{
for (int i=0;i<n;i++)
*first++=value++;
}
void main(int argc,char* argv[])
{
int n=2;
vector<int> v;
v.reserve(3);
iota_n(v.begin(),n,100);
random_shuffle(v.begin(),v.end());
copy(v.begin(),v.end(),ostream_iterator<int>(cout,"\n"));
}
应该随机输出1到100的整数，结果却什么也没有输出，求真相。
[解决办法]
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
template <class ForwardIterator, class T>
void iota_n(ForwardIterator first, int n,T value)
{
for (int i=0;i<n;i++)
*first++=value++;
}
void main(int argc,char* argv[])
{
int n=2;
vector<int> v(3);
iota_n(v.begin(),n,100);
random_shuffle(v.begin(),v.end());
copy(v.begin(),v.end(),ostream_iterator<int>(cout,"\n"));
}
or the following way
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
template <class ForwardIterator, class T>
void iota_n(ForwardIterator first, int n,T value)
{
for (int i=0;i<n;i++)
*first++=value++;
}
void main(int argc,char* argv[])
{
int n=2;
vector<int> v;
v.resize(3)
iota_n(v.begin(),n,100);
random_shuffle(v.begin(),v.end());
copy(v.begin(),v.end(),ostream_iterator<int>(cout,"\n"));
}