c++ - 如何使用for循环C++将不同的值输入到二维指针到指针数组中

Question

我创建了两个数组，friends 和 timechat。我不想编写手动将每条数据放入二维数组的长代码，而是想用 for 循环来完成。我创建了一个二维数组，2 列和 5 行。一栏必须有其他时间的所有 friend 的名字。我哪里错了？

代码:

string **friendslist;
friendslist = new string*[10];

for (int i = 0; i < 10; i++)
    friendslist[i] = new string[10];


string friends[5] = {"Bob","Rob","Jim","Hannah","James"};
string timechat[5] = {"12:00", "5:00", "22:00", "18:30", "11:45"};

for (int i = 0; i < 5; i++)
{
    for (int j = 0; j < 2; j++)
    {
        friendslist[j][i] = friends[i];
        cout << friendslist[j][i] << " ";
    }
    cout << endl;
}
cin.get();

Answer 1

我已经对所有内容进行了去乱码处理，并将其置于推荐的新手风格中，并带有特别显式的变量名……在这个阶段这对你来说非常重要。我故意忽略了您的timechat，这样您就可以先掌握数组机制和循环。关于更好地利用 std:: 库与 arrays、vectors 和 maps 的建议很好，但应该会出现之后。首先理解这一点，以及为什么/如何与您的不同:

#include <iostream>
#include <string>

using namespace std;

const int NUMBER_OF_LISTS_OF_FRIENDS = 2;
const int NUMBER_OF_FRIENDS_IN_ONE_LIST = 5;

int main(int argc, const char *argv[]) {
  // put your constant data at top
  string friends[NUMBER_OF_FRIENDS_IN_ONE_LIST] = {"Bob","Rob","Jim","Hannah","James"};

  string **friendslist;
  friendslist = new string*[NUMBER_OF_LISTS_OF_FRIENDS]; // Two lists of friends

  // Allocate your storage
  for (int init_list_index = 0; init_list_index < NUMBER_OF_LISTS_OF_FRIENDS; init_list_index++) {
    // each friend list is of length 5
    friendslist[init_list_index] = new string[NUMBER_OF_FRIENDS_IN_ONE_LIST];
  }


  // Initialize the storage with useful contents
  for ( int list_index = 0; list_index < NUMBER_OF_LISTS_OF_FRIENDS; list_index++ ) {
    for (int friend_index = 0; friend_index < NUMBER_OF_FRIENDS_IN_ONE_LIST; friend_index++ ) {
      friendslist[list_index][friend_index] = friends[friend_index];
    }
  }

  // output all the values in a clear format as an initialization check
  for ( int list_index = 0; list_index < NUMBER_OF_LISTS_OF_FRIENDS; list_index++ ) {
    for (int friend_index = 0; friend_index < NUMBER_OF_FRIENDS_IN_ONE_LIST; friend_index++ ) {
      cout << "list " << list_index << ", friend index " << friend_index << ": "
           << friendslist[list_index][friend_index] << "\t";
    }
    cout << endl;
  }
}