Question

这是一个相当简单的问题。我希望用户输入一个类型。在我的代码中，如果用户想要输入“科幻小说”，它就不会打印任何东西。但是，如果我将“.txt”文件从“科幻小说”改为“科幻小说”，那就会打印出来。所以，我猜它与间距有关。如何使用户也可以输入两个带空格的单词。：

#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <iomanip>

using namespace std;

bool compareByTitle(struct Movie m1,struct Movie m2);
void printYear(vector<Movie> &d);
void printGenre(vector<Movie> &d);
void printDirector(vector<Movie> &d);
void printDuration(vector<Movie> &d);
char *capitalize(char* name);
void printAllMovies(vector<Movie> &d);

struct Movie{
        string title;
        string director;
        string genre;
        string year;
        string duration;

    } m;


int main()
{
    ifstream inputFile;
    string line;
    vector<Movie> myMovies;
    char choice, again;

    inputFile.open("Movie_entries.txt");
    while (getline(inputFile, line))   // reads a line from the file
    {
        //cout << line << endl;
        stringstream lineStream(line);   // transforms the line into a stream

        // get fields from the string stream; fields are separated by comma
        getline(lineStream, m.title, ',');
        getline(lineStream, m.director, ',');
        getline(lineStream, m.genre, ',');
        getline(lineStream, m.year, ',');
        getline(lineStream, m.duration, ',');


        myMovies.push_back(m);
    }
    inputFile.close();

sort(myMovies.begin(),myMovies.end(), compareByTitle);


cout << "Please choose on of the following:\n\n"
     << "A - Display all movies listed\n"
     << "B - Display movies in a specific year\n"
     << "C - Display movies in a specific genre\n"
     << "D - Display movies from a specific director\n"
     << "E - Display movies in a specific duration\n"
     << "Enter your choice: ";
     cin >> choice;

//Input validation
while (toupper(choice) != 'A' && toupper(choice) != 'B' && toupper(choice) != 'C' &&
       toupper(choice) != 'D' && toupper(choice) != 'E'){

    cout << "Choice is invalid, the choice must be one of the following: 'A', 'B', 'C', 'D' or"
         << " 'E'. \n"
         << "Please try again: ";
    cin >> choice;
}



cout << endl << endl;

switch(choice)
{
    case 'a':
    case 'A': printAllMovies(myMovies); break;
    case 'b':
    case 'B': printYear(myMovies); break;
    case 'c':
    case 'C': printGenre(myMovies); break;
    case 'd':
    case 'D': printDirector(myMovies); break;
    case 'e':
    case 'E': printDuration(myMovies); break;
}


return 0;
}

bool compareByTitle(Movie m1, Movie m2)
{

    return m1.title[0] < m2.title[0];

}

void printAllMovies(vector<Movie> &d)
{
    for(int i = 0; i < d.size(); i++)
    {
    cout << d[i].title << ", " << d[i].director << ", " << d[i].genre << ", "
         << d[i].year << ", " << d[i].duration << endl << endl;
    }
}

void printYear(vector<Movie> &d)
{
    string whatYear;
    cout << "Enter a specific year: ";
    cin >> whatYear;

    for(int i = 0; i < d.size(); i++)
    {
        if(whatYear==d[i].year)
        {


         cout << d[i].title << ", " << d[i].director << ", " << d[i].genre << ", "
             << d[i].year << ", " << d[i].duration << endl << endl;
        }
    }
}

void printGenre(vector<Movie> &d)
 {

    string whatGenre;
    cout << "Enter a specific genre: ";
    getline(cin, whatGenre);
    cin >> whatGenre;

for(int i = 0; i < d.size(); i++)
    {
        if(whatGenre==d[i].genre)
        {
         cout << d[i].title << ", " << d[i].director << ", " << d[i].genre << ", "
              << d[i].year << ", " << d[i].duration << endl << endl;
        }
    }
 }

void printDirector(vector<Movie> &d)
{
    string whatDirector;
    cout << "Enter a specific director: ";
    getline(cin, whatDirector);
    cin >> whatDirector;




    for(int i = 0; i < d.size(); i++)
    {
        if(whatDirector==d[i].director)
        {


         cout << d[i].title << ", " << d[i].director << ", " << d[i].genre << ", "
             << d[i].year << ", " << d[i].duration << endl << endl;
        }
    }
}

void printDuration(vector<Movie> &d)
{
    string whatDuration;
    cout << "Enter a specific duration: ";
    cin >> whatDuration;

    for(int i = 0; i < d.size(); i++)
    {
        if(whatDuration==d[i].duration)
        {


         cout << d[i].title << ", " << d[i].director << ", " << d[i].genre << ", "
             << d[i].year << ", " << d[i].duration << endl << endl;
        }
    }
}

Answer 1

在void printGenre(vector<Movie> &d)

getline(cin, whatGenre); << reads in genre from user
cin >> whatGenre; << reads in the genre again, but this time only one word of it.

第二次阅读whatGenre覆盖了第一个。为什么这样做？嗯......这就是我们需要查看更多代码的原因。

回到main

cin >> choice;

读入单个字符。但要获得该角色，用户必须提供角色并按回车键。输入保留在输入流中，由

解析

getline(cin, whatGenre);

并将生成的空字符串放在whatGenre。

中

小心在>>和std::getline之间来回翻转。最好只使用一个。

解决方案：

删除

cin >> whatGenre;

并替换

cin >> choice;

带

string choicestr;
getline(cin, choicestr);
choice = choicestr[0];

或类似的东西。

你也必须为你的其他一些功能做同样的事情。

如何让用户合并空间

1 个答案: