String input problem

[cjjack88]

Hi, i am new in c++. I am doing an assignment where I need a menu for user to select the operation.

My menu coding is as below.

int main()
{
    myCarSystem b;
    char ch;
    string temp1, temp2;
    double temp3, temp4;
    while(1)
    {
       cout<<endl<<endl;
       cout<<" My Car System Operations "<<endl;
       cout<<" ----------------------------- "<<endl;
       cout<<" 1. Insertion/Creation "<<endl;
       cout<<" 2. In-Order Traversal "<<endl;
       cout<<" 3. Removal "<<endl;
       cout<<" 4. Exit "<<endl;
       cout<<" Enter your choice : ";
       cin>>ch;
       switch(ch)
       {
           case 1 : cout<<" Enter car model to be inserted : " <<endl;
                    fflush(stdin);
                    getline(cin, temp1);
                    cout<<"\n Enter car colour type : "<<endl;
                    fflush(stdin);
                    getline(cin, temp2);
                    cout<<"\n Enter car price : "<<endl;
                    fflush(stdin);
                    cin>>temp3;
                    cout<<"\n Enter car deposit : "<<endl;
                    fflush(stdin);
                    cin>>temp4;
                    b.insert(temp1, temp2, temp3, temp4);
                    break;
           case 2 : cout<<endl;
                    cout<<" In-Order Traversal "<<endl;
                    cout<<" -------------------"<<endl;
                    b.print_inorder();
                    break;
           case 3 : cout<<" Enter data to be deleted : ";
                    cin>>temp1;
                    b.remove(temp1);
                    break;
           case 4 : system("pause");
                    return 0;
                    break;
       }
    }

    return 0;
}

My problem is, when user is selects the operation, like example user selects 1 to enter car information, the screen will jump back to the menu and skip the input information part.
please help me to check this problem.
Thank you.
Cjjack88.

[amrith92]

Try adding a cin.ignore(); statement before each of your inputs.

See this: http://www.cplusplus.com/reference/iostream/istream/ignore/

Incidentally, its better you don't use fflush(stdin); . See here for more info.

[cjjack88]

Thank you for reply.

I add cin.ignore();, but the problem still occur.

[cjjack88]

int main()
{
    myCarSystem b;
    char ch;
    string temp1, temp2;
    double temp3, temp4;
    while(1)
    {
       cout<<endl<<endl;
       cout<<" My Car System Operations "<<endl;
       cout<<" ----------------------------- "<<endl;
       cout<<" 1. Insertion/Creation "<<endl;
       cout<<" 2. In-Order Traversal "<<endl;
       cout<<" 3. Removal "<<endl;
       cout<<" 4. Exit "<<endl;
       cout<<" Enter your choice : ";
       cin>>ch;
       switch(ch)
       {
           case 1 : cout<<" Enter car model to be inserted : " <<endl;
                    fflush(stdin);
                    cin.ignore(256, ' ');
                    getline(cin, temp1);
                    cout<<"\n Enter car colour type : "<<endl;
                    fflush(stdin);
                    cin.ignore(256, ' ');
                    getline(cin, temp2);
                    cout<<"\n Enter car price : "<<endl;
                    fflush(stdin);
                    cin.ignore();
                    cin>>temp3;
                    cout<<"\n Enter car deposit : "<<endl;
                    fflush(stdin);
                    cin.ignore();
                    cin>>temp4;
                    b.insert(temp1, temp2, temp3, temp4);
                    break;
           case 2 : cout<<endl;
                    cout<<" In-Order Traversal "<<endl;
                    cout<<" -------------------"<<endl;
                    b.print_inorder();
                    break;
           case 3 : cout<<" Enter data to be deleted : ";
                    cin>>temp1;
                    b.remove(temp1);
                    break;
           case 4 : system("pause");
                    return 0;
                    break;
       }
    }

    return 0;
}

[cjjack88]

Try adding a cin.ignore(); statement before each of your inputs.

See this: http://www.cplusplus.com/reference/iostream/istream/ignore/

Incidentally, its better you don't use fflush(stdin); . See here for more info.

int main()
{
    myCarSystem b;
    char ch;
    string temp1, temp2;
    double temp3, temp4;
    while(1)
    {
       cout<<endl<<endl;
       cout<<" My Car System Operations "<<endl;
       cout<<" ----------------------------- "<<endl;
       cout<<" 1. Insertion/Creation "<<endl;
       cout<<" 2. In-Order Traversal "<<endl;
       cout<<" 3. Removal "<<endl;
       cout<<" 4. Exit "<<endl;
       cout<<" Enter your choice : ";
       cin>>ch;
       switch(ch)
       {
           case 1 : cout<<" Enter car model to be inserted : " <<endl;
                    cin.ignore();
                    getline(cin, temp1);
                    
                    cout<<"\n Enter car colour type : "<<endl;
                    cin.ignore();
                    getline(cin, temp2);
                    
                    cout<<"\n Enter car price : "<<endl;
                    cin.ignore();
                    cin>>temp3;
                    
                    cout<<"\n Enter car deposit : "<<endl;
                    cin.ignore();
                    cin>>temp4;
                    
                    b.insert(temp1, temp2, temp3, temp4);
                    break;
           case 2 : cout<<endl;
                    cout<<" In-Order Traversal "<<endl;
                    cout<<" -------------------"<<endl;
                    b.print_inorder();
                    break;
           case 3 : cout<<" Enter data to be deleted : ";
                    cin>>temp1;
                    b.remove(temp1);
                    break;
           case 4 : system("pause");
                    return 0;
                    break;
       }
    }

    return 0;
}

The problem still same.
Anyway thank you for the information.

[amrith92]

If cin.ignore(); fails, then try clearing the input stream, before accepting input. This can be done with cin.clear(); .

If all your inputs are failing, then maybe try the following:

1. Clear the input stream.
2. Read the rest of the characters in the stream into a temporary string.
3. Accept the user's input

So, for example, the statements to do this might be:

cin.clear();
        string rubbish;
        cin >> rubbish;

[csurfer]

Before worrying about big things please pay some attention towards small things...
There is a lot of difference between 1 and '1' .
The input you are taking is a character so the cases of switch should be as case '1' : case '2' : and all , else make the input to be taken to a integer rather than a character.

And ya usage of fflush(stdin) is bad. One more point of concern is all the inputs you are taking doesn't actually need a space and hence you don't even need to use getline().You can directly use cin >> temp1; 4 posts without even concentrating on the main problem.This way you will add all the statements in this world but still wont be able to take the inputs.

[cjjack88]

I found where is the problem. I did a careless mistake.
amrith92 , thank you for your help and informations.

[cjjack88]

Before worrying about big things please pay some attention towards small things...
There is a lot of difference between 1 and '1' .
The input you are taking is a character so the cases of switch should be as case '1' case '2' and all , else make the input to be taken to a integer rather than a character.

And ya usage of fflush(stdin) is bad. One more point of concern is all the inputs you are taking doesn't actually need a space and hence you don't even need to use getline().You can directly use cin >> temp1;

Thank you for reply. I did a careless mistake.