onst和volatile分析

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一、const和volatile分析

　　1、const修饰变量

　　# 在c语言中const修饰的变量时只读的，其本质还是变量

　　# const修饰的变量会在内存占用空间

　　# 本质上const只对编译器有用，在运行时无用

　　原来const不是真的常量

onst和volatile分析

# 在C语言中const修饰的数组是只读的

　　#const修饰的数组空间不可以被改变

　　const int A[5] = {1, 2, 3, 4, 5}

　　int *p = (int *)A;

　　int i = 0;

　　for(i=0; i<5; i++)

　　{

　　p[i] = 5-i;//报错

　　}

　　3、const修饰指针

　　# const int *p; //p可变，p指向的内容不可变

　　# int const *p; //p可变，p指向的内容不可变

　　# int *const p; //p不可变，p指向的内容可变

　　# const int *const p; //p不可变， p指向的内容不可变

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