指针做形参

指针做形参

void point(int *p)
{
printf("2. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//其地址变了，说明是另一变量；指向的内存块数据和值没变
int i = 10;
*p = i;
printf("3. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//地址和值没变；指向的内存块数据改变
i = 7;
printf("4. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//地址和值指向的内存块数据都不变
}
void point1(int *p)
{
printf("7. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//其地址变了，说明是另一变量；指向的内存块数据和值没变
int i = 10;
p = &i;
printf("8. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//p的值改变为i的地址，即p指向i，此时p与r分别指向不同的内存块了，不会互相影响
i = 7;
printf("9. p = %d, addr p = %d, the p is %p\n", *p, &p, p);//p指向i，i指向的内存数据改变，p也跟着改变
}
int main()
{
int i = 6;
int a = 6;
int *q = &i;
int *r = &a;
printf("1. q = %d, addr q = %d, the q is %p\n", *q, &q, q);
point(q);
printf("5. q = %d, addr q = %d, the q is %p\n", *q, &q, q);
printf("6. r = %d, addr r = %d, the r is %p\n", *r, &r, r);
point1(r);
printf("10. r = %d, addr r = %d, the r is %p\n", *r, &r, r);
return 1;
}

print
1. q = 6, addr q = 3340996, the q is 0032FAD4
2. p = 6, addr p = 3341004, the p is 0032FAD4
3. p = 10, addr p = 3341004, the p is 0032FAD4
4. p = 10, addr p = 3341004, the p is 0032FAD4
5. q = 10, addr q = 3340996, the q is 0032FAD4
6. r = 6, addr r = 3341000, the r is 0032FAD0
7. p = 6, addr p = 3341004, the p is 0032FAD0
8. p = 10, addr p = 3341004, the p is 0032FAD8
9. p = 7, addr p = 3341004, the p is 0032FAD8
10. r = 6, addr r = 3341000, the r is 0032FAD0
请按任意键继续. . .