Question

我正在开展一项应该对人们最喜欢的饮料进行调查的作业。理想情况下，它将继续要求用户为他们希望包括的每个人提交喜爱的饮料。当用户完成所有投票后，他或她输入-1并显示计数。我注意到的唯一问题是，当结果打印出来时，我会得到每种饮料的任意大数字。我仍然是编码的新手，甚至更新的C ++，但它是否与switch语句的范围有关？它似乎根本没有增加饮料的数量：/。

#include <iostream>
#include <stdlib.h>

using namespace std;

int main()
{
    int input, vcoff, vtea, vcoke, voj, personNumber = 1;

     cout << "Welcome to the favorite beverage survey. Our beverage options are: "<< endl;
     cout << "1.Coffee   2.Tea   3.Coke   4.Orange Juice" << endl;
     cout << endl;
     cout << "Please input the favorite beverage of person # " << personNumber << ": Choose 1, 2, 3, or 4 from the"<< endl << "above menu or -1 to exit the program."<< endl;
     cin >> input;

  while (input < -1)
  {
    cout << "That is not an option. Please reenter a valid number: " << endl;
    cin >> input;
  } 

  while (input > 0)
  {
    switch(input)
    {
    case 1: vcoff++;
    break;
    case 2: vtea++;
    break;
    case 3: vcoke++;
    break;
    case 4: voj++;
    break;
    default: cout << "Sorry, that's not a menu item. Please try again: " << endl;
    cin >> input;
    }
    personNumber++;
     cout << "Please input the favorite beverage of person # " << personNumber << ": Choose 1, 2, 3, or 4 from the"<< endl << "above menu or -1 to exit the program."<< endl;
     cin >> input;
  } 

 if (input = -1)
 {
   cout << "The total number of people surveyed is " << personNumber << ". The results are as follows:" << endl;
   cout << "Beverages     Votes" << endl << "**********************" << endl;
   cout << "Coffee:    " << vcoff << endl;
   cout << "Tea:    " << vtea << endl;
   cout << "Coke:    " << vcoke << endl;
   cout << "Orange Juice:    " << voj << endl;
 }

return 0;
}

Answer 1

你错过了变量的初始化。如果你不这么说，局部变量不会初始化为0。

这意味着起始值可以是任何不可预测的值，这可以解释您发现奇怪的数字。

尝试：

int input=0, vcoff=0, vtea=0, vcoke=0, voj=0, personNumber = 1;

Answer 2

而不是int input, vcoff, vtea, vcoke, voj, personNumber = 1; 执行int input = 0, vcoff = 0, vtea = 0, vcoke = 0, voj = 0, personNumber = 1;初始化变量。

初学者C ++饮料调查报告

2 个答案: