本文介绍了用C位设置的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我试图做到以下几点:
I tried it like this but not getting correct answers. Can anyone tell where I am wrong?
unsigned setbits(unsigned x,int p,int n,unsigned y)
{
return (x>>p & (y|(~0<<n)));
}
解决方案
Something like:
unsigned setbits(unsigned x,int p,int n,unsigned y)
{
unsigned mask = (1U << n) - 1U; // n-bits
y &= mask; // rightmost n bits of y
y <<= p; // which begin at position p
mask <<= p; //idem
x &= ~mask; //set the 0s
x |= y; //set the 1s
return x;
}
Or if you want to do it in fewer lines, more difficult to debug, but waaaay cooler:
unsigned setbits(unsigned x,int p,int n,unsigned y)
{
unsigned mask = (1U << n) - 1U; // n-bits
return (x & ~(mask << p)) | ((y & mask) << p);
}
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