## Week02_指標 ### 指標_1 ```c #include <stdio.h> int main() { int a=10,b=20,c=30; printf("n1:%d n2:%d n3:%d\n", a,b,c); int *p=&a; *p=200; printf("n1:%d n2:%d n3:%d\n", a,b,c); } ``` ![](https://i.imgur.com/CtNZRa6.png) ### 指標_2 ```c #include <stdio.h> int main() { int a=10,b=20,c=30; printf("n1:%d n2:%d n3:%d\n", a,b,c); int *p=&a; *p=200; printf("n1:%d n2:%d n3:%d\n", a,b,c); int *p2=&c; *p2=300; printf("n1:%d n2:%d n3:%d\n", a,b,c); } ``` ![](https://i.imgur.com/8HzXhv7.png) ### 指標_3 ```c #include <stdio.h> int main() { int a=10,b=20,c=30; printf("n1:%d n2:%d n3:%d\n", a,b,c); int *p=&a; *p=200; printf("n1:%d n2:%d n3:%d\n", a,b,c); int *p2=&c; *p2=300; printf("n1:%d n2:%d n3:%d\n", a,b,c); p2=p; *p2=400; printf("n1:%d n2:%d n3:%d\n", a,b,c); } ``` ![](https://i.imgur.com/8vBYl1s.png) ### 指標_4 ```c #include <stdio.h> int main() { int a[3]={10,20,30}; printf("a[0]:%d a[1]:%d a[2]:%d\n", a[0],a[1],a[2]); int *p=&a[0]; *p=200; printf("a[0]:%d a[1]:%d a[2]:%d\n", a[0],a[1],a[2]); int *p2=&a[2]; *p2=300; printf("a[0]:%d a[1]:%d a[2]:%d\n", a[0],a[1],a[2]); p2=p; *p2=400; printf("a[0]:%d a[1]:%d a[2]:%d\n", a[0],a[1],a[2]); } ``` ![](https://i.imgur.com/ZMz6s5O.png)