带结构的c ++ getline（）

Question

struct car
{
  string name;
  int year;
};    

int main() {
    int noOfCars;
    cout<<"enter no_ of cars : ";    
    cin>>noOfCars;    
    car* cars = new car[noOfCars];    
    for(int i=0;i<noOfCars;i++)
    {
        cout<<"Car #"<<i<<endl;
        cout<<"Name : ";    
        getline(cin,(cars[i].name));  //here is the problem 
        cout<<"\n year : ";    
        cin>>cars[i].year;    
        cout<<endl;
    }
}

something wron with taking a whole line as a string input to the name in the strcut,doesn't even take any thing and proceeds to ge the year directly ... :S ???

it works with cin,but i want to take a whole line ! and it works with strings globally defined,but not with this inside the struct

Answer 1

This has been explained so many times as chris says.

The problem is in your preceding input call

cin>>noOfCars;

This reads a number, ie it reads digits, it does not read a newline. You might type a newline but that doesn't mean that it gets read. In fact the newline is left over until the next time you read, which is your getline call. So your first getline call reading the newline that has been left over from when you read the number of cars.

It doesn't surprise me that newbies get this wrong, but it does indicate that you should spent some time researching your problem before asking a question. This has been asked and answered hundreds of times before.

Answer 2

Insert cin.ignore( 1000, '\\n' ); after getline .

#include<string>
#include<iostream>
using namespace std;

struct car
{
  string name;
  int year;
};    

int main() {
    int noOfCars;
    cout<<"enter no_ of cars : ";    
    cin>>noOfCars;    
    car* cars = new car[noOfCars];    
    for(int i=0;i<noOfCars;i++)
    {
        cin.clear();


        cout<<"Car #"<<i<<endl;
        cout<<"Name : ";    
        getline(cin,(cars[i].name));  //here is the problem 

     cin.ignore( 1000, '\n' );

        cout<<"\n year : ";    
        cin>>cars[i].year;    
        cout<<endl;

    }
    return 0;
}

Answer 3

The problem is that cin>>noOfCars leaves the newline generated by the Enter key in the input queue. The getline(cin,(cars[i].name)) is simply reading that newline character and assigns a null string to the car[i].name array. And since at the end of your loop cin>>cars[i].year does the same thing over and over, getline(cin,(cars[i].name)) is always reading a newline character before it lets you input anything.

To fix this you just need to discard the newlines character after cin reads noOfCars and cars[i].year , which can be cleanly done by concatenating a cin.get() after your cin s like this:

cout<<"enter no_ of cars : ";    
(cin>>noOfCars).get();            //here is the solution
car* cars = new car[noOfCars];    
for(int i=0;i<noOfCars;i++)
{
    cout<<"Car #"<<i<<endl;
    cout<<"Name : ";    
    getline(cin,(cars[i].name));  //here is the problem 
    cout<<"\n year : ";    
    (cin>>cars[i].year).get();   //here is the solution 
    cout<<endl;
}

Answer 4

Try cin.getline(Cars[i].name,streamsize); Where streamsize is the maximum size of the string. I think that's the simplest form.