---
tags: 系統程式
---
# **系統程式ch2、3:電腦的硬體結構、組合語言**
**[以下圖片來自陳鍾誠老師網站教材](http://ccckmit.wikidot.com/)**


### 指標範例

#include <stdio.h>
char a[10];
int c= 2;
int *cptr= &c;
char b[] = "Hello world";
char *aptr =a, *bptr=b;
// *aptr = *bptr;
int main(){
    printf("0x%p 0x%p 0x%p 0x%p\n ",bptr,&b,cptr,&c);//位置
   
    printf("%s %d",bptr,cptr);//Hello world
    // 0x0040401C 0x0040400C 0x00404004 0x00404004
    // Hello world 4210692
}

### 字串複製-指標

#include <stdio.h>
char a[10];
char b[] = "Hello world";
char *aptr =a, *bptr=b;
int main(){
    while(1){
        *aptr = *bptr;
        printf("a =%c b= %c \n ",*aptr,*bptr);
        aptr++;
        bptr++;
        printf("0x%p 0x%p \n ",aptr,bptr);//位置
        if(*bptr =='\0')
            break;
    }
}
/*執行結果
 a =H b= H
 0x00407075 0x00404005
 a =e b= e
 0x00407076 0x00404006
 a =l b= l
 0x00407077 0x00404007
 a =l b= l
 0x00407078 0x00404008
 a =o b= o
 0x00407079 0x00404009
 a =  b=
 0x0040707A 0x0040400A
 a =w b= w
 0x0040707B 0x0040400B
 a =o b= o
 0x0040707C 0x0040400C
 a =r b= r
 0x0040707D 0x0040400D
 a =l b= l
 0x0040707E 0x0040400E
 a =d b= d
 0x0040707F 0x0040400F */