求助，为什么cinAC了，getline却错了

求助，为什么getline和cin效果不一样，如下 我用的拼接字符串读入，cinAC了，getline就红了几个

```cpp
while (cin>>str1)
{
    len++;
    str += str1;
}

while (getline(cin, str1))
{
    len++;
    str += str1;
}

main函数：

    int main()
    {
        int len = 0, cnt = 0;
        string str, str1;
        while (getline(cin, str1))
        {
            len++;
            str += str1;
        }
        printf("%d ", len);
        if (str[0] == '1')
        {
            printf("0 ");
        }
        char pre = str[0];
        for (int i = 0; str[i]; i++)
        {
            if (str[i] == '0' || str[i] == '1')
            {
                if (str[i] == pre)
                {
                    cnt++;
                }
                else
                {
                    printf("%d ", cnt);
                    cnt = 1;
                }
                pre = str[i];
            }
        }
        printf("%d ", cnt);
        return 0;
    }