How do I clear recent screen output instead of having to CLS everything and outputting the whole screen again?

[Tiger58]

Question is pretty much everything I have to ask. The reason I am clearing screen and outputting it all again is that I don't want the ERROR message output to be piling up after the user messes up on the input. I'll show an example to help understand.

Example output of what I don't want:

Enter a choice: 
1. Chocolate
2. Vanilla
3. Strawberry
4. Banana;
ERROR. Enter 1-4:
ERROR. Enter 1-4:
ERROR. Enter 1-4:

Example of what I am doing:

int main()
{
	int option;

	cout<<"Enter a choice: "<<endl;
	cout<<"1. Chocolate"<<endl;
	cout<<"2. Vanilla"<<endl;
	cout<<"3. Strawberry"<<endl;
	cout<<"4. Banana"<<endl;
	cin>>option;
	while(option<1 || option>4)
	{
		cin.clear();
		cin.ignore(10000,'\n');
		system("CLS");

		cout<<"ERROR. Enter 1-4: "<<endl;
		cout<<"1. Chocolate"<<endl;
		cout<<"2. Vanilla"<<endl;
		cout<<"3. Strawberry"<<endl;
		cout<<"4. Banana"<<endl;
		cin>>option;
	}
}

A professor suggested gotos as a solution, but they seem to be the ugly duckling around here. What are my options? Do I need to change my method at all to make it more efficient? Is my current method as bad as gotos?

[Pured]

DO NOT use goto.

int main()
{
	int option = 0;

	    cout<<"Enter a choice: "<<endl;
	    cout<<"1. Chocolate"<<endl;
	    cout<<"2. Vanilla"<<endl;
	    cout<<"3. Strawberry"<<endl;
	    cout<<"4. Banana"<<endl;
	    cin>>option; //get input

	while(option<1 || option>4)
	{
                system("clear"); //removes previous
		cout<<"ERROR. Enter 1-4: "<<endl;
		cout<<"1. Chocolate"<<endl;
		cout<<"2. Vanilla"<<endl;
		cout<<"3. Strawberry"<<endl;
		cout<<"4. Banana"<<endl;
		cin>>option;
            }
	}
}

Problem with this code is that if the user inputs a character, the program will break.

[Tiger58]

Problem with this code is that if the user inputs a character, the program will break.

That is why I used the cin.clear() function. Hmm did you see my code at all? You wrote what I basically did, except without the cin.clear() and cin.ignore().

[xismn]

What's wrong with outputting everything again?

[nvrmnd]

Is my current method as bad as gotos ?

No, and the only thing bad about goto is when you get them mixed up, multiple labels, multiple goto's .... ugly

But possibly one can write a code that cls at custom position so you don't reapeat the menu again, but you need to learn win32 or other console advance stuffs first

[Duthomhas]

Are you sure your professor meant the goto language construct and not the goto character position function?
http://www.google.com/search?btnI=1&q=msdn+SetConsoleCursorPosition

Print your menu, etc. Use GetConsoleScreenBufferInfo() to learn where the cursor is, print your question, wait for user input, if input is bad, SetConsoleCursorPosition() to where it was, write a whole bunch of spaces (as approriate), go back again and print the new prompt.
http://www.google.com/search?btnI=1&q=msdn+GetConsoleScreenBufferInfo

It's a messy solution, but probably easiest for you to start.

Good luck.

[Tiger58]

Thank you, yes now that you mention it he did say something about gotoxy, something similar to that.

[Duthomhas]

The gotoxy() function is found in <conio.h>. If you are using an old Borland C++, you can #include it and use it.