在32位操作系统下，任何类型的指针变量都占四个字节,为什么输出结果是8呢

Question

#include<stdio.h>
struct INFO
{
        int a;
        char b;
        double c;
};
int main()
{
        int *p;
        char *p1;
        float *p2;
        double *p3;
        struct INFO *p4;   //struct INFO类型为结构体类型 
        void *p5;
        printf("int point size is :%d\n",sizeof(p));
        printf("char point size is :%d\n",sizeof(p1));
        printf("float point size is :%d\n",sizeof(p2));
        printf("double point size is :%d\n",sizeof(p3));
        printf("struct point size is :%d\n",sizeof(p4));
        printf("void point size is :%d\n",sizeof(p5));
        return 0;
}