c++ - 测试结构和数组时出现 msvcr110d.dll!memcpy 错误

Question

我想知道是否有人可以看看为什么我会在这里遇到运行时错误。

First-chance exception at 0x6FBDEBC2 (msvcr110d.dll) in Project1.exe: 0xC0000005: Access violation writing location 0x7CB67DEB. Unhandled exception at 0x6FBDEBC2 (msvcr110d.dll) in Project1.exe: 0xC0000005: Access violation writing location 0x7CB67DEB.

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main(){
    struct person {
        string name;
        int age;
        int weight;
        string nickname;
    } ;

    person people[1];

    for(int i = 0; i < sizeof(people); i++){
        string s[4];
        for(int x = 0; x < 4; x++){
            cout << "Please enter person " << i << "'s " << (x == 0 ? "name" : x == 1 ? "age" : x == 2 ? "weight" : x == 3 ? "nickname" : "unknown") << "." << endl;
            getline(cin, s[x]);
        }
        people[i].name = s[0];
        stringstream(s[1]) >> people[i].age;
        stringstream(s[2]) >> people[i].weight;
        people[i].nickname = s[3];
    }

    for(int i = 0; i < sizeof(people); i++)
        cout << "Person " << i << ": name = " << people[i].name << ", age = " << people[i].age << ", weight = " << people[i].weight << ", nickname = " << people[i].nickname << endl; 

    cout << "Please press enter to continue.";
    fflush(stdin);
    cin.clear();
    cin.get();
}

在第二个 for 循环之前一切正常，似乎运行错误。

Answer 1

你的问题出在这里:

sizeof(people)

这不会给您people 数组的长度，而是给您数组的总大小(以字节为单位)。您可以使用 std::begin(people) 和 std::end(people) 使迭代器到达数组的开头和结尾。

for (auto it = std::begin(people); it != std::end(people); ++it)
{
  // it is an iterator to an element of people
  it->name = ....;
}

或者，您可以使用基于范围的循环:

for (auto& p : people)
{
  // p is a reference to an element of people here
  p.name = ....;
}