const 与 auto-526互联

auto关键字在推断类型时，如果没有引用符号，会忽略值类型的const修饰，而保留修饰指向对象的const，典型的就是指针

#include <iostream>
#include <boost/type_index.hpp>

int main() {
    using boost::typeindex::type_id_with_cvr;
    int a = 10;
    int b = 20;

    const int* p1 = &a;
    p1 = &b;   // right
    *p1 = 30;  // wrong
    
    int* const p2 = &a;
    p2 = &b;   // wrong
    *p2 = 40;  // right

    auto tp1 = p1;
    tp1 = &b;   // right
    *tp1 = 30;  // wrong

    auto tp2 = p2;
    tp2 = &b;   // right
    *tp2 = 40;  // right

    const int c = 10;
    auto tc = c;

    // 输出 int const * (等价于 const int *)
    std::cout << type_id_with_cvr<decltype(tp1)>().pretty_name() << std::endl;
    // 输出 int *
    std::cout << type_id_with_cvr<decltype(tp2)>().pretty_name() << std::endl;
    // 输出 int
    std::cout << type_id_with_cvr<decltype(tc)>().pretty_name() << std::endl;

    return 0;
}

const

auto