help with fgets

**n3cr0_l0rd** · 06-06-2009

Code:

#include <conio.h>
#include <iostream.h>

struct movies
{
    char name[50];
    char director[50];
    int rel;
};

struct movies m1[20];

int main()
{
    int i,n,view;
    do
    {
        cout<<"How many records do u want to input ? ";
        cin>>n;
    }while(n>20 || n<0);
    for(i=0;i<n;i++)
    {
        cout<<"\nEnter name : ";
        fgets(m1[i].name,50,stdin);
        cout<<"Enter the director's name : ";
        fgets(m1[i].director,50,stdin);
        cout<<"Enter release date : ";
        cin>>m1[i].rel;
    }

    cout<<"\n\nEnter the year you want to view : ";
    cin>>view;

    for(i=0;i<n;i++)
    {
        if(view==m1[i].rel)
        cout<<"\n"<<m1[i].name;
    }

    getch();
    return 0;
}

I can input both the strings. "Enter the name" and "Enter the director's name" get printed together in a row before i can input anything.... Plz run the program for details regarding what the problem is..

**n3cr0_l0rd** · 06-06-2009

and yes, i suppose i haven't followed the standards... sorry for that, i will surely do it next time after i get well acquainted with it

**bithub** · 06-06-2009

When you use cin to input an integer, it will leave the newline character in the input stream. The next time you call fgets() it will read up to that newline and assume you input an empty string. Try adding

Code:

cin.ignore();

after each call where you input an integer.

And since you already posted about it, I wont make a comment about your failure to write standard C++ code

**grumpy** · 06-06-2009

You're mixing the methods of input and output. Both C I/O functions (like fgets()) and C++ iostreams are allowed to do things independently - most notably, buffer the output to the standard output devices. There is no guarantee they will be synchronised.

Either use C I/O functions (eg fprintf(stdout ....) with fgets()) or C++ streams (eg cout and cin). Not both at once.

[Yes - it is possible to use them together, but the techniques introduce even more opportunities for you to get yourself in trouble if you're not extremely careful, so I won't explain how].

Unrelated to your problem : <conio.h> and getch() are not standard C or C++.

**Elysia** · 06-07-2009

Don't use char, use std::string. They can easily be read using the >> operator of cin.

**n3cr0_l0rd** · 06-07-2009

@Elysia ^^!!

Okay, then i am not supposed to use fgets in with C++ I/O streams... so what shall i do to input an string... just using cin doesn't help with string with spaces..

btw, that was my first C++ code... I would like to know about the C++ standards if anyone is willing to help..

Thx

**n3cr0_l0rd** · 06-07-2009

I am still searching over the net without any success... huh...

**Elysia** · 06-07-2009

You can get use std::getline instead. It will read spaces (NOT std::cin.getline).

**n3cr0_l0rd** · 06-07-2009

error: no match for 'operator>>' in 'std::getline >> m1[i].movies::name'

i replaced cin with std::getline and got that errror.. could you plz elaborate it... sry but never done c++ before this...

i did some editing trying to follow the standards... Hope its better than last one..

Code:

#include <iostream>
using namespace std;
struct movies
{
    std::string name;
    std::string director;
    int rel;
};

struct movies m1[20];

int main()
{
    int i,n,view;
    do
    {
        cout<<"How many records do u want to input ? ";
        cin>>n;
    }while(n>20 || n<0);
    for(i=0;i<n;i++)
    {
        cout<<"\nEnter name : ";
        std::getline>>m1[i].name;
        cout<<"Enter the director's name : ";
        std::getline>>m1[i].director;
        cout<<"Enter release date : ";
        cin>>m1[i].rel;
    }

    cout<<"\n\nEnter the year you want to view : ";
    cin>>view;

    for(i=0;i<n;i++)
    {
        if(view==m1[i].rel)
        cout<<"\n"<<m1[i].name<<"\n";
    }

    system("pause");
    return 0;
}

**grumpy** · 06-07-2009

If you're trying to read a C-style string (array of char) getline() is a member function of the istream classes, not an object.

If you wish to read a std::string from a string, then getline() is a function accepts two arguments by reference: the stream to be read from and the string to be read.

Both forms of getline() can accept an additional (optional) argument that specifies the delimiter if you want reading to stop on something other than a newline.

Either way, you can find out about them by reading your library documentation.

**Elysia** · 06-07-2009

You must learn to read documentation, because std::getline is not an object - it's a function!
getline - C++ Reference

**ninety3gd** · 06-07-2009

here is how I would use a string with a struct;

Code:

struct exam
{
    string name;
};

int main()
{
    exam aStudent;

// reading in..
   cout << "Enter a name" << endl;
   getline(cin, aStudent.name);
    

    //Print out...

    cout << "Exam blah..." << aStudent.name;

    return 0;
 }

**n3cr0_l0rd** · 06-08-2009

Sorry but i didnt get how i referred getline as object ? My teachers suck at teaching... so could you plz explain it... seriously, you plz suggest me a FREE e-book so i can learn everything from scratch, just C++...

**tabstop** · 06-08-2009

Originally Posted by n3cr0_l0rd

Sorry but i didnt get how i referred getline as object ?

Here, for instance:

Code:

std::getline>>m1[i].name;

you are treating getline as something you can read from, as opposed to something that you do.

**n3cr0_l0rd** · 06-08-2009

blame me for being dependent on teacher as he never said what :: and >>/<< acutually mean... any source i can learn all the basics of c++? Now i feel too much desperate for knowing nothing...

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