移位运算注意

32位数值移位后存入64位数值，注意类型转换，不然会溢出。

#include <stdio.h>

int main(int argc, char **argv)
{
    long long t = 1;
    for (int i = t; i <63; ++i)
    {
        t = (t<<1);
        printf("%d %lld\n", i, t);
    }
    for (int i = 0; i < 63; ++i)
    {
        t = ((long long)1 << i);
        printf("%d %lld\n", i, t);
    }

    return 0;
}