loop problem

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November 14th, 2002, 07:44 AM

Neildadon

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loop problem

having a problem with this small c++ program im writing.

i'm getting an error saying Lvalue required at the first while statement

this program loops printing just the message until the user enter 'n' or 'N'. If the user enters a character other than 'n' , 'N' , 'y' , 'Y' the message invalid selection is entered and the prompt should be redisplayed

can anyone please help?

#include <iostream.h>
# include <stdlib.h>
char ch;
void main()
{
while (ch=!'n' || ch=!'N')
{
cout << "Do you really want to run this program? (yes/no)\n ";
cin >> ch ;

if (ch!='y' || ch!='Y' || ch!='n' || ch!='N')
{
cout << "Invalid selection\n" ;
}

}

if (ch=='n' || ch=='N')
{
exit(1);
}

}

November 14th, 2002, 08:23 AM

Onslaught

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Code:

#include <iostream.h>

int main() {
        char ch='\0';

        while (ch!='y' && ch!='Y') {
                cout << "Do you really want to end this program (y/n)?";
                cin >> ch;

                if (ch!='Y' && ch!='y' && ch!='N' && ch!='n')
                        cout << "Invalid selection.\n";
        }
        cout << "End of program.\n";
        return(1);
}

The following code worked as expected with me.

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November 14th, 2002, 06:27 PM

Analyser

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Quote:

while (ch=!'n' || ch=!'N')

The not-equal operator is "spelled" as != instead of as =!. You seem to use it the right way further down in your code.

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November 14th, 2002, 09:52 PM

TechNoFear

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while(toupper(ch)!='Y')//get rid of all lower case

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