Question About Getline

**bengreenwood** · 04-28-2009

Hi,

I've been programming some examples out of a book and I've noticed something about getline that's made me curious. In the following simple program, you enter a make and model of a car, and then it outputs it.

But say you change the line "cin.getline(make, 19);" to "cin.getline(make, 3);". Then, if you enter something like "ford" or anything longer than that, the program no longer asks you the second question. How come?

Code:

#include <iostream>
using namespace std;

char model[20];
char make[20];

int main()
{
    cout << "Enter make: ";
    cin.getline(make, 19);
    cout << "Enter model: ";
    cin.getline(model, 19);

    cout << make << " " << model;
    return 0;
}

Thanks.

**bithub** · 04-28-2009

Because there are still characters in the input buffer since the first cin.getline() call did not read everything. The characters that are left over get assigned to model.

**anon** · 04-28-2009

Actually not. When the line is longer the stream goes into a failed state.

For this reason getline with C style strings is hard to use (I've never used it in practice). Use std::string, its version of getline and you won't have these worries:

Code:

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


int main()
{
    string make, model;
    cout << "Enter make: ";
    getline(cin, make);
    cout << "Enter model: ";
    getline(cin, model);

    cout << make << " " << model;
    return 0;
}

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