vectors and cin, getline?

This is a discussion on vectors and cin, getline? within the C++ Programming forums, part of the General Programming Boards category; hi, for some reason the line "cout << "Enter your name : "; getline(cin, name);" is acting up. can someone ...

  1. #1
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    vectors and cin, getline?

    hi,

    for some reason the line "cout << "Enter your name : "; getline(cin, name);" is acting up. can someone please check it out for me? i'm using it with vectors and a class.

    file.cpp
    Code:
    #include <iostream>
    #include <string>
    #include <vector>
    #include "file.h"
    using namespace std;
    
    int my_class::askUser()
    {
    	cout << "Enter your name : ";	getline(cin, name);
    	cout << "building number : ";	cin >> build_num;
    	cout << "apartment number: ";	cin >> apt_num;
    //	cout << "Enter your name : ";	getline(cin, name);     //placing it here gives me the same problem
    return 0;
    }
    
    void my_class::dispInfo() const
    {
    	cout << "customer name is "		<< name			<< endl;
    	cout << "building number is "	<< build_num	<< endl;
    	cout << "apartment number is "	<< apt_num		<< endl;
    }
    
    int main()
    {
    vector<my_class> one(6); int i;
    
    		for(i=0; i<one.size(); i++)
    		{
    		one[i].askUser();
    		one[i].dispInfo();
    		}
    
    return 0;
    }
    file.h
    Code:
    #include <iostream>
    #include <string>
    using namespace std;
    
    class my_class
    {
    public:
    	int askUser();
    	void dispInfo() const;
    
    private:
    	int build_num;
    	int apt_num;
    	string name;
    };
    on run, after the first execution of the loop, it should ask for the the string input again but it skips it. i have no idea how to correct it. the logic is perfect i think.

    thanks,
    barneygumble742

  2. #2
    Cat without Hat CornedBee's Avatar
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    >> doesn't consume the newline from the input. getline snaps it up and immediately returns. I suppose that's your problem.
    All the buzzt!
    CornedBee

    "There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code."
    - Flon's Law

  3. #3
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    so what can i use besides getline that will work? i would like to try getc but isn't that only for characters?

  4. #4
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    Continue to use getline, but after you call cin >> you must ignore the extra newline. The simple way to do that is to add cin.ignore(); between a call to cin>> and a call to getline.

  5. #5
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    could you explain where to put the cin.ignore(); ?

    i put it at the very top and after the getline and both ways it acts very weird.

  6. #6
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    Code:
    cout << endl;
    cin >> myvariable;
    cin.ignore();
    cout << endl;
    getline(cin, myvariable2);

  7. #7
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    read this for more detail.
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  8. #8
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    hi...this is what i did and it works fine and i'm able to put it in the member function regardless the location. i don't know why i didn't think of this to begin with.

    Code:
    int my_class::askUser()
    {
    string first, last;
    	cout << "Enter your name : ";	cin >> first >> last;
    		name = first + " " + last;
    	cout << "building number : ";	cin >> build_num;
    	cout << "apartment number: ";	cin >> apt_num;
    return 0;
    }
    thanks again everyone. i'm keeping all your recommendations.

  9. #9
    *this
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    Code:
    int my_class::askUser()
    {
    string first, last;
    	cout << "Enter your name : ";	cin >> first >> last;
    		name = first + " " + last;
            cin.ignore();   //catch the return key so you dont leave it in the stream
    	cout << "building number : ";	cin >> build_num;
    	cout << "apartment number: ";	cin >> apt_num;
    return 0;
    }
    OR...
    Code:
    int my_class::askUser()
    {
    string name;
    	cout << "Enter your name : ";	getline(cin, name);
    	cout << "building number : ";	cin >> build_num;
    	cout << "apartment number: ";	cin >> apt_num;
            cin.ignore();   //catch the return key so you dont leave it in the stream
    return 0;
    }
    Last edited by JoshR; 07-02-2005 at 12:33 AM.

  10. #10
    *this
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    Quote Originally Posted by barneygumble742
    hi...this is what i did and it works fine and i'm able to put it in the member function regardless the location. i don't know why i didn't think of this to begin with.

    Code:
    int my_class::askUser()
    {
    string first, last;
    	cout << "Enter your name : ";	cin >> first >> last;
    		name = first + " " + last;
    	cout << "building number : ";	cin >> build_num;
    	cout << "apartment number: ";	cin >> apt_num;
    return 0;
    }
    thanks again everyone. i'm keeping all your recommendations.
    You will still have the same problem as before, you are leaving the return character in the stream. But now since all your variables are taken care of, it doesnt seem appearant to you. Just read everyones post, I think cin.ignore(); should be stuck in your brain by now.
    Last edited by JoshR; 07-02-2005 at 02:52 AM.

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