C++中的移位问题

Question

在以下C/C++代码中，为什么结果还是41，根本没变
unsigned int d=41;
d=(d<<32)>>32;
cout<<" 结果"<<d;
所用电脑是win10 64位系统，VS2015和DEV-C++结果都是这样。
移位操作中还有哪些是值得我们注意的？

Answer 1

c++标准约定当位移右侧操作数等于左侧操作数的位的个数时，运算会导致未定义行为。

5.8.1 The operands shall be of integral or unscoped enumeration type and integral promotions are performed. The type of the result is that of the promoted left operand. The behavior is undefined if the right operand is negative, or greater than or equal to the length in bits of the promoted left operand.