ignore w/o using ignore function

[jupitertrooper]

Ok, I am newish at programming in c++ and am doing a computer science program in school. For my latest project I have come to a bit of a dead end and was hoping for some help with loops and ignoring characters.

The program is quite simple, it is a tax calculator. The program asks the user if they have any dependents. The user must answer with a y/Y/n/N(this part is fine, and is not where I am having issues) or it is acceptable for the user to enter a word. In the case that a user enters a word, I have to take the first character of the word and if it is a(n) y/Y/n/Y then the input is valid, and all other characters are ignored. If the first character is not a(n) Y/y/n/N then it is supposed to fail and then I have to use while loops.

My problem is I don't know how to ignore all characters after the first, and just validate the first character. I would really appreciate help on this. Oh, and I cannot use cin.ignore().

The program then goes on to promt the user for their income, then calculates it, this part I have no problem with.

Thanks for your help.

[VernonDozier]

You isolate a character int a string using the [] operator.

string input = "yes";
char firstLetter = input[0];

if (firstLetter == 'y' || firstLetter == 'Y' || firstLetter == 'n' || firstLetter = 'N')
   cout << "Input is valid\n";
else
   cout << "Input is invalid.\n";

[Ancient Dragon]

>>My problem is I don't know how to ignore all characters after the first

Use getline() to get the entire string from the keyboard, then follow Vernon's suggestion.

[jupitertrooper]

well it looks like your guys stuff will work, unfortunately I can only use what I learned in class.

I have to do this:
The program must keep asking the user for an answer until it is correct.
If the first data item on the line is correct(y/Y/n/N) then it can be used. Regardless, all other data on the line must be ignored.
Note that you are not permitted to use strings - you may only use variables of type char and float. As well, you cannot use the function ignore.

Basically I am only allowed to use cout, cin, loops(mostly while loops for this program) and I guess if/else statements.

Any ideas? I have tried a variety of do while and just while loops, and even tried if loops, but I am getting no where.

[Tom Gunn]

For the sake of not doing your homework, I will offer some advice only. The last character you will read on the line is '\n'. So if you read and ignore characters in a loop until '\n' is found, it will have the same effect as this call to ignore:

cin.ignore(numeric_limits<streamsize>::max(), '\n');

[jupitertrooper]

I may have solved my problem, I was using || instead of && in the while statements, and switching them seems to have solved my problem, I'll get back to you guys if it isn't the solution.