复制代码 代码如下:
#include <stdio.h>

int main (void)
{
unsigned int MAX = 32;
unsigned int index = 31;

index = 31;
index = (index + 1) % MAX; // 这个容易理解
printf ("index = %d\n", index);

index = 31;
index = (index + 1) & (MAX - 1); // 这个运算效率高
printf ("index = %d\n", index);

return;
}

$ ./a.exe
index = 0
index = 0