string-memory-test.cc

#include <iostream>
using namespace std;


char get_first_char(string *str) {
    return (*str)[1] + 2;
}

void string_memory(){
    long bottom = -1;
    string word = "dev";
    cout << get_first_char(&word) << endl;

    cout << "> Current string content: " << word << endl;
    cout << " &bottom: " << &bottom << endl;
    cout << "   &word: " << &word << endl;
    char &c1 = word[0];
    cout << "&word[0]: " << (void *)&c1 << endl;
    auto size = (char *)&bottom - (char *)&word;
    cout << " sizeof word: " << size << endl;

    long *pword = (long *)&word;
    cout << " 0. " << std::hex << *pword << endl;
    cout << " 1. " << std::hex << *(pword + 1) << endl;
    cout << " 2. " << std::hex << *(pword + 2) << endl;

    // 长度超过 24 怎么办
    cout << string(40, '-') << endl;
    word = string(33, 'C');
    cout << "   &word: " << &word << endl;
    char &c2 = word[0];
    cout << "&word[0]: " << (void *)&c2 << endl;
    cout << " 0. " << std::hex << *pword << endl;
    cout << " 1. " << std::hex << *(pword + 1) << endl;
    cout << " 2. " << std::hex << *(pword + 2) << endl;
}

int main() {
    string_memory();
    return 0;
}