Thread: while (scan != 'y' or 'n) or if(scan != 'y' or 'n)

Code:

#include <iostream>
#include <string>
#include <cstdlib>
#include <stdlib.h>
#include <windows.h>
#include <stdio.h>
#include <time.h>
using namespace std;

int Wait ( int Seconds );

int main ( void )
{
char scan;
while (scan != 'n')
{
string a("Norton anti virus scanning \n");
string c("7 Hits\n");
string d("Viruses found: 4\n");
string e("Code red Worm\n");
string f("Nimda Virus\n");
string g("Love Bug Virus\n");
string h("Kevlarsmart Worm\n");
string j("Trojans: 3\n");
system("cls");
cout << "scan system? Y or N: ";
cin >> scan;
cout << a;
Wait (5);
cout << c;
Wait(3);
cout << d;
cout << e;
cout << f;
cout << g;
cout << h;
cout << "No files fixed\n";
Wait(2);
cout << j;
cout << "No files fixed\n";
Wait(4);
cout << "Scan again? Y or N: ";
cin >> scan;
    {
    while (scan != 'y' or 'n')
    cout << "Invalid command";
    Wait(2);
    return 0;
    }
}
}
int Wait ( int Seconds )
{
    clock_t endtime = clock() + Seconds * CLOCKS_PER_SEC;
    while ( ( clock() < endtime ) );
    return 0;
}

I can type s at the start and it scans. at the end, however, i get:

Invalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid

Forever and ever.
No matter what i type.
Should i use a goto loop, a while loop, or if, or what?
How can i fix that?

It looks like this at the end:

_________________________________
_________________________________
Scan again? Y or N: n
Invalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid
Invalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid commandInvalid
_____________________________
_____________________________

Well, its repeating because of this line:

Code:

while (scan != 'y' or 'n')

You're taking the "or" of two expressions, "scan != 'y'" and "'n'". 'n' will always evaluate as true because it is nonzero. The correct way to write this expression is

Code:

while ((scan != 'y') && (scan != 'n'))

Also, it will loop because you said or instead of and, cause scan will always be either not equal to 'y' or not equal to 'n'.

Actually I'm surprised that your compiler let you say "or" instead of "||"; I thought it was just Perl that would let you do that.

Oh, and please use "int main" instead of "void main", this is C++ not C.

thanks, the int main( void ) is for the timer, as i can't get it to work if i delete it. my include files are for the void. i don't what i can use in place of it.

and it still doesn't work right. i still get infinite Invalid command.

im using dev c++ 4, with a patch which allows c, c++, ascii, perl and java.

Hmm...are you inputting a capital Y or N? If you are, they won't be equal to lowercase y or n. If you want to catch this you'll need to account for it in your while statement.

now it's working. download it to see the remaining error... i need to input it twice. feel free to fix any bugs.