C語言指針的實驗說明

<div align="left"><pre class="cpp" name="code">上午上《編譯原理》的時候聽老師談到了C語言的指針的問題，有些疑問，所以回到宿捨進行了實驗驗證。 

<p>當函數參數是個指針的時候，當調用這個函數時，此函數的形參的得到的是指針本身，還是他的一個副本？如下代碼：</p><p>#include "stdio.h" 
 
void change1(int* d) 
{ 
    printf("address_d = %d  d = %d  *d = %d\n", &d, d, *d); 
    int s = 4; 
    d = &s; 
    printf("address_d = %d  d = %d  *d = %d\n",&d, d, *d); 
} 
 
void change2(int *e) 
{ 
    *e = 5; 
} 
 
int main() 
{ 
    int *p(NULL); 
    int *q(NULL); 
    int a(1); 
    while(a) 
    { 
        scanf("%d", &a); 
        printf("address_a = %d  a = %d\n", &a, a); 
        p = &a; 
        q = p; 
                printf("address_P = %d  p = %d  *p = %d\n", &p, p, *p); 
                printf("address_q = %d  q = %d  *q = %d\n", &q, q, *q); 
        change1(q); 
                printf("address_q = %d  q = %d  *q = %d\n", &q, q, *q); 
        change2(q); 
        printf("address_a = %d  a = %d\n", &a, a); 
        printf("address_q = %d  q = %d  *q = %d\n", &q, q, *q); 
                printf("address_P = %d  p = %d  *p = %d\n", &p, p, *p); 
    } 
} 
</p> 

作者 wche1990