关于c ++：const，指针，typedef和stars


const, pointers, typedefs and stars

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what is the difference between const int*, const int * const, int const *

大家好，

我想知道，当指针涉及到以下内容时，是否有人可以提供关于typedef语法的一些清晰信息：-恒星位置的含义；-const位置的含义；-二者之间的相互作用。

在我写了下面的例子之后，我对const和star发生了什么有了一个大致的了解，但是我只是通过尝试和错误得到了代码，我想从一个知识渊博的人那里得到一个更理论上的解释。

谢谢

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#include <iostream>
using namespace std;

int main() {
    int paolo = 10;

    // POINTERS
    typedef int* PointerToInt1;
    typedef int *PointerToInt2;

    // POINTERS TO CONST
    typedef const int* PointerToConstInt1;
    typedef const int *PointerToConstInt2;
    typedef int const* PointerToConstInt3;
    typedef int const *PointerToConstInt4;
    // qualifying with const twice
    // ignored -  simply gets you a warning
    typedef const int const* PointerToConstInt5;
    typedef const int const *PointerToConstInt6;

    // CONST POINTERS
    typedef int *const ConstPointerInt1;
    typedef int* const ConstPointerInt2;

    // CONST POINTERS TO CONST
    typedef const int *const ConstPointerToConstInt1;

    //  POINTERS
    int *ip1 = &paolo;
    int* ip2 = &paolo;
    PointerToInt1 ip3 = &paolo;
    PointerToInt2 ip4 = &paolo;

    // POINTERS TO CONST
    PointerToConstInt1 ip11;
    PointerToConstInt2 ip12 = &paolo;
    PointerToConstInt3 ip13;
    PointerToConstInt4 ip14 = &paolo;
    PointerToConstInt3 ip15;
    PointerToConstInt4 ip16 = &paolo;

    /*
    //  POINTERS TO CONST
    //ALL ERROR
    *ip11 = 21;     *ip12 = 23;
    *ip13 = 23;     *ip14 = 23;
    *ip15 = 25;     *ip16 = 23;
    */

    // CONST POINTERS
    // ERROR - No initialiser
    // ConstPointerInt1 ip21;    
    // ConstPointerInt2 ip22;
    int me = 56;
    int you = 56;
    ConstPointerInt1 ip21 = &me;    
    ConstPointerInt1 ip22 = &me;    
    *ip21 = 145;
    *ip22 = 145;

    // ERROR - No initialiser
    // ConstPointerToConstInt1 ip31;

    // ERROR - Cant change  eobjected pointed at
    ConstPointerToConstInt1 ip31 = &me;
    // ip31 = &you;

    // ERROR - Cant change  the value of objected pointed at
    ConstPointerToConstInt1 ip33 = &me;
    // *ip31 = 54;


    cout << *ip1 << *ip2 <<  *ip4 <<   endl;
    cout << *ip11 <<  *ip12 << *ip13 << *ip14 << *ip15 <<  *ip16 << endl;


    return 1;

}
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(P)我不知道但我会给你一个答案。(p)(P)一种类型的多字母标语不需要多字母标语。(p)字母名称(P)空间并不真的重要在这里。(p)字母名称(P)EDOCX1 3 Diversal means point can point to a different location but the value in the location it is pointing at cannot be changed.(p)(P)字母名称4它无法确定不同的地点，但它可以改变地点中的价值。由于这是一个固定的观点，因此必须首先作出声明。(p)(P)EDOCX1是指一个恒定值的恒定点。这一点可能与地点不同，也可能改变地点中的价值。So，it must be initialized while declaration.(p)字母名称(P)如果你能理解这一可怕的错误，EDOCX1的音标3和EDOCX1的音标4可以轻松理解。希望有帮助！(p)

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(P)For general rules on using EDOCX1 pental 0，there are billions of questions here on stackoverflow.For instance：const usage with pointers in C.(p)(P)Regarding typedefs，the rule for writing a typedef is the same for writing a variable declaration；the only difference is that you prefix it with EDOCX1 disciplinary 1，and replace the name of the variable with the name of the typedef！(with a few exceptions，which are typically fixed with parents).So，for instance:(p)字母名称(P)贝卡：(p)字母名称

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