combination of getline and cin

[Nele]

Hello,

When I use cin to read a line (like a number or char), then my program skips the first getline() it sees. After that, it continues as normal.
I found a solution by adding a getline() that I don't use afterwards, but I can't believe that is the way to solve this...

Anyone who can help me?

I add the working code here, so you know what I mean (It only works if I add the string 'strange' and read a line with it, though I don't actually read the line)

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


int main ()
{
	string mystr;
	string strange;
        string name;
	int year;
	
	cout << "Enter name: ";
	getline (cin,name);
	cout << "Enter year: ";
	cin >> year;
        getline (cin, strange);
	cout << "Do you like this friend?";
	getline (cin,mystr);

	cout << "\nYou have entered the friend: \n";
	cout << name;
	cout << "\t(" << year << ") \n";
        cout << "Do you like this friend: " << mystr << "\n";
	return 0;
}

[martinlb]

since "year" is an "int" variable, "cin>>year" extracts only a numeric value, leaving the end-of-line that follows in the input buffer.
you can better control input if you only do getlines with strings, and extract other types from them using stringstreams..., try substituting "cin>>year" by:

string yearstring;
getline(cin,yearstring);
stringstream(yearstring) >> year;

[hazda]

Wat about removing the unnecessary getline and typing in cin.ignore();
just after the cin >> year; ? it works,im just amazed why martinlb solves this in many lines of codes. If there is anything wrong with my method,please explain it martin

[martinlb]

Nothing wrong with your code, hazda. It actually does what Nele asked.

What I suggested is a method to better control input: Performing extractions directly on cin (using "cin>>") can be problematic in terms of expected behavior - not only for the case Nele was pointing out, but also for example if the user enters a word when a number is expected, weird things happen...

By separating user input and extraction operations, that can be avoided - so I always recommend to use this instead of extracting directly from cin.

[Nele]

Thanks for the help!

Actually, the code I submitted was a simplified part of the code I was working on. In the real case, I want to read in a char.

So I suppose with getline, it should go something like:

char c;
string mystr;
getline(cin,mystr);
c=mystr[0];

Is that correct? I find it difficult knowing when to use a string or a vector of chars...

But I'm also wondering: if I would use

string myst;
int year;
getline (cin,myst);
stringstream(myst) >> year;

and the user would type some characters, instead of a number, won't there be an error as well, when trying to use stringstream?

Anyway, thanks a lot already for the help!

[AzraelUK]

If you just want to grab a single character, then getch(); might be a better choice.