指针与常量

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520，‘a’，3.14

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	#define PRICE 520
#define A 'a'
#define PI 3.14

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	- const int price = 520;
- const char a = 'a';
- const float pi = 3.14;

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//对const关键字定义的变量赋值
#include<stdio.h>
int main(){
const float pi = 3.14;
printf("%fn",pi);
pi = 3.1415;
return 0;
}

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error: assignment of read-only variable 'pi'

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#include<stdio.h>
int main(){
const int num = 520;
const int *p=&num;
*p = 1024;
}

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error: assignment of read-only variable 'pi'

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#include<stdio.h>
int main(){
int num = 520;
//const int cnum = 888;
const int *pc = num;
printf("num:%d,%num%pn",num,&num);
printf("*pc:%d,pc:%pn",*pc,pc);
*pc = 1024;
}

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[Error] assignment of read-only location '*pc'

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#include<stdio.h>
int main(){
int num = 520;
const int cnum = 888;
int * const p = &num;
*p = 1024;
printf("*p:%dn",*p);
}

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#include<stdio.h>
int main(){
int num = 520;
const int cnum = 888;
int * const p = &num;
*p = 1024;
printf("*p:%dn",*p);
p = &cnum;
printf("*p:%dn",*p);
}

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#include<stdio.h>
int main(){
int num =520;
const int cnum = 888;
const int * const p = &num;
const int * const *pp = &p;
printf("pp:%p,&p:%pn",pp,&p);
printf("*pp:%p,p:%p,&num:%pn",*pp,p,&num);
printf("**p:%d,*p:%d,num:%dn",**pp,*p,num);
}