c++ - 从二进制编码中提取小时、分钟和秒

Question

我写了一个程序来解决下面的练习。我弄对了小时和分钟，但我弄错了秒。

In order to save disk space Time field in the directory entry is 2 bytes long. Distribution of different bits which account for hours, minutes and seconds is given below:

15 14 13 12 11|10  9  8  7  6  5| 4  3  2  1  0
 H  H  H  H  H| M  M  M  M  M  M| S  S  S  S  S

Write a C++ Program that take input two-byte time entry and appropriately separates hours, minutes and seconds using suitable bitwise operators.

#include<iostream>
using namespace std;
int main()
{
    unsigned int hours, mins, secs;
    unsigned int time;
    cout << "enter time ";
    cin >> time;
    hours = (time >> 11);
    mins = ((time << 5) >> 10); 
    secs = ((time << 11) >> 11);
    cout << hours << "  " << mins << "  " << secs << endl;
    return 0;
}

为了得到分钟，我将输入向左移动 5 个位置，希望消除所有 H 位，然后向右移动 10 个位置以消除所有 S 位并且在最右边的位置有 M 位。

对于秒也是如此。

但是，如果我输入 445，我希望结果为 13 分 29 秒，但程序输出 0 13 445。

为什么小时和分钟显示正确，但秒显示不正确？

Answer 1

secs = time & 0x1F; // This should give the 5 bits you're expecting for seconds.