c++ - 我得到一个 "string subscript out of range error"。我不明白为什么

Question

我搜索了网站，但找不到解决问题的方法。我尝试进行微小的更改，但没有解决任何问题。我不断收到“字符串下标超出范围”错误。我不知道为什么。也许我是盲人，我在某处遗漏了一个小错误。现在我在这里请求帮助。

程序信息:该程序将输入名字和姓氏，对其进行验证并应用大小写转换。用户输入名字和姓氏后，它将清除屏幕并显示用户输入的名字。然后它会输入产品评级，对其进行验证并应用大小写转换。显示一个标题，后跟一个与 5 个产品值(value)相对应的条形图。

编辑:我想对帮助过我的人说声谢谢。谢天谢地，我终于解决了这个问题。我不得不说这里有一个很棒的社区，而且 react 非常好。我现在要去上课，但我会为将来可能遇到同样问题的人发布我更新的代码。再次非常感谢你们。

#include <iostream>
#include <string>

using namespace std;

void Name (string, string&, const int);
void Rating (string&, int[], const int);

void main()
{
    const int MAX_FIRST_NAME = 20;
    const int MAX_LAST_NAME  = 25;
    const int MAX_PRODUCTS   =  5;

    string  firstNameQuestion = "First Name";
    string  lastNameQuestion  = "Last  Name";

    string    firstName;
    string     lastName;
    string ratingString;

    int ratingInt [MAX_PRODUCTS];


    while (true)
    {
        Name (firstNameQuestion, firstName, MAX_FIRST_NAME);

        if (firstName == "Quit")
            break;

        Name (lastNameQuestion, lastName, MAX_LAST_NAME);

        if (lastName == "Quit")
            break;

        system ("cls");

        cout << "First Name: "  << firstName;
        cout << endl;
        cout << "Last  Name: "  << lastName;
        cout << endl;
        cout << endl;

        Rating (ratingString, ratingInt, MAX_PRODUCTS);
    }   
}

void Name (string question, string& answer, const int MAX)
{
    int count;

    do
    {
        cout << question << " (" << MAX << " chars max. type \"quit\" to stop):     ";
        getline (cin, answer);
    }
    while (answer.empty() || answer.length() > MAX);

    answer[0] = toupper (answer[0]);

    for (count = 1; count < answer.length(); count++)
        answer[count] = tolower ( answer[count] );
}

void Rating (string& ratingString, int ratingInt[], const int MAX)
{
    int  count;
    int    who;

    for (count = 0; count < MAX; count++)
    {
        do
        {
            cout << "Rating for product no." << count + 1 << " (A to E): ";
            cin  >> ratingString[count];
            ratingString[count] = toupper (ratingString[count]);
        }   
        while (ratingString.empty() || ratingString.length() > 1 ||     ratingString[count] > 'E');
    }

    for (who = 0; who < MAX; who++)
    {
        if (ratingString[who] == 'A')
            ratingInt[who] = 10;

        if (ratingString[who] == 'B')
            ratingInt[who] = 8;

        if (ratingString[who] == 'C')
            ratingInt[who] = 6;

        if (ratingString[who] == 'D')
            ratingInt[who] = 4;

        else 
            ratingInt[who] = 2;
    }

    cout << endl;
    cout << endl;
    cout << "Consumer satisfaction bar chart: ";
    cout << endl;

    for (count = 0; count > MAX; count++)
    {
        cout << endl;
        cout << "Product #" << count + 1 << "      ";

        for (who = 0; who > ratingInt[count]; who++)

            cout << "*";
    }
}

Answer 1

第 45 行

Rating (ratingString, ratingInt, MAX_PRODUCTS);

ratingString 为空。 当运行到Line76时

    cin  >> ratingString[count];

您正在引用边界外的索引。

这个编辑怎么样:

    char cc;
    cin  >> cc;
    ratingString.push_back(cc);