我认为我的C++教科书给了我一些关于switch语句的错误

Question

#include <iostream>

using namespace std;

int main()
{

    int grade;
    int aCount;
    int bCount;
    int cCount;
    int dCount;
    int fCount;

    cout << "Enter the letter grades." << endl
        << "Enter the EOF character to end input." << endl;

    while ((grade = cin.get()) != EOF)
    {

        switch (grade)
        {
        case 'A':
        case 'a':
            aCount++;
            break;

        case 'B':
        case 'b':
            bCount++;
            break;

        case 'C':
        case 'c':
            cCount++;
            break;

        case 'D':
        case 'd':
            dCount++;
            break;

        case 'F':
        case 'f':
            fCount++;
            break;

        case '\n':
        case '\t':
        case ' ':
            break;

        default:
            cout << "Incorrect letter grade entered." << "Enter a new grade." << endl;
            break;
        }
    }

    cout << "\n\nNumber of students who received each letter grade:"
        << "\nA: " << aCount
        << "\nB: " << bCount
        << "\nC: " << cCount << "\nD: " << dCount << "\nF: " << fCount << endl;

    system("PAUSE");
    return 0;
}

这是我的C++教科书提供的精确代码.当我通过复制这些代码然后编译它来练习这些switch语句代码时,我的Visual Studio 2010 express keep给了我一个错误,说"aCount正在使用而没有分配......"同样适用于fCount.该程序应该从键盘读取A到F的任何字母,然后增加任何被识别的字母.我认为在代码中某处应该有cin >> grade但我找不到它.顺便说一句,"cin.get()"可以作为cin >> grade？

Answer 1

当你声明你的变量时,尝试给它们0这样的值:

int grade = 0;
int aCount = 0;
int bCount = 0;
int cCount = 0;
int dCount = 0;
int fCount = 0;

这将确保您在变量使用之前实际上为变量赋值.

然后尝试运行它,我敢打赌它有效!