C++，如何未知长度的string输入数组

如代码，我发现程序在运行时会跳过cin.get，这是怎么回事啊？另外，关于将未知长度的字符串输入数组，还有什么好办法吗？

 int main()
{
    int time;
    scanf("%d", &time);
    int count=0;
    while(count < time)
    {
        string str;
        char temp;
        int i;

        while((temp=cin.get())!='\n')
        {
                str +=temp;
        }
        length =str.length();

        char* preorder = new char[length];
        char* inorder = new char[length];

        for(i = 0;i<length;i++)
        {
            preorder[i]=str[i];
        }

        for(i=0;i<length;i++)
        {
            scanf("%c", inorder[i]);
        }

        sort(preorder, inorder, length);

        count++;
        delete preorder;
        delete inorder;
    }
    return 0;
}