Question

c++程序，将vector中的数据复制到数组中，程序报错

#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> a;
int b;
while(cin >>b)
{
a.push_back(b);
}
int *str = new int[a.size()];
int *tp = str;
vector<int> ::iterator c;
for ( c = a.begin() ; c != a.end() ; ++c,++str)
{
*tp = *c;
}
for (int d =0 ; d != a.size() ; ++d)
{
cout <<*(tp +d) <<endl;
}
delete [] str;
return 0;
}

//我删掉delete[]str后可以正常运行，请问这是什么情况

Answer 1

#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> a;
int b;
while(cin >>b)
{
a.push_back(b);
}
int *str = new int[a.size()];
int *tp = str;
vector<int> ::iterator c;
for ( c = a.begin() ; c != a.end() ; ++c,++str)
{
*str = *c; //这里是*str=*c
}
for (int d =0 ; d != a.size() ; ++d)
{
cout <<*(tp +d) <<endl;
}
delete [] tp; //因为str已经改变，所以用delete[] tp来释放内存
return 0;
}

Answer 2

for ( c = a.begin() ; c != a.end() ; ++c,++str)
{
*tp = *c;
}
这个循环里面你自加了str，所以你最后释放str失败了，因为str的值已经改变了
按照你的程序应该修改为
for ( c = a.begin() ; c != a.end() ; ++c,++tp)//str改为tp
{
*tp = *c;
}
tp=str;//给tp重新赋值，不然下面不对