Blue Bridge Cup Eliminate last one (bit operation, code completion)

requirement ：

The following code represents an integer binary representation of the rightmost consecutive 1 All become 0 If the last one is 0, Then the original number remains unchanged .

Need to complete the code

#include <stdio.h>

void f(int x)
{
    int i;
    for(i=0; i<32; i++) printf("%d", (x>>(31-i))&1);
    printf("....");
    
    x =  _______________________;
    
    for(i=0; i<32; i++) printf("%d", (x>>(31-i))&1);
    printf("\n");    
}

int main()
{
    f(128+64+2);
    f(128+64+15);
    f(128+64+1);
    
    return 0;
}

answer ：x&(x+1)

analysis ：

First of all, clarify what to achieve in space , Observe the empty front and back x Binary conversion of , That is to say, the empty line should realize the end 1 The transformation of

Now analyze how to get rid of 1, We should put the continuous tail 1 All become 0, First of all, we have to create 0 Just come , Because of a pile of 11111 Add a 1 You'll get equal 0, So there must be an answer x+1

then x+1 Followed by a continuous tail 1 All become 0, The rest , Continuous tail 1 The higher position of the becomes 1, The rest has not changed

take x And x+1 By comparison, we can find , Every one of you , It is both Same as 1 by 1, Same as 0 by 0, Different for 0, You can get the destination binary , Think of biting and , The answer comes out

eg：

x:        101010111

x+1:    101011000

The goal is ：101010000