位图算法 C语言

#include <stdio.h>  

void set_bit(void *base, unsigned long n)  
{  
    unsigned long *m = (unsigned long*) base;
    unsigned long size = sizeof(unsigned long) * 8;
    m[ n / size ] |= 1UL << (n % size);
}  

void clear_bit(void *base, unsigned long n)  
{  
    unsigned long *m = (unsigned long*) base;
    unsigned long size = sizeof(unsigned long) * 8;
    m[ n / size ] &= ~(1UL << (n % size));
}  

int main()  
{  
    unsigned long value[2] = {0};
    set_bit(value, 0);  
    set_bit(value, 63);  
    printf("Set:\n");
    printf("0x%016lx, 0x%016lx\n", value[0], value[1]);  
    clear_bit(value, 0);  
    clear_bit(value, 63);  
    printf("Clear:\n");
    printf("0x%016lx, 0x%016lx\n", value[0], value[1]);  
    return 0;  
}