Input not being read properly by if condition statement - c++

Question

one would think this is easy, but for some odd reason, my conditional statement is ignoring user input.
If I input a character 'N' or 'n' it still executes the 'Y' portion of the conditional statement, have a look:
while (i < 10) {
cout << "Would you like "<< nameOfDish[i] << "? Please enter Y or N.\n";
cin >> userResponse;
if (userResponse == 'y' || 'Y')
{
cout << "How many orders of " << nameOfDish[i] << " would you like?\n";
cin >> quantityOfDish[i];
if (quantityOfDish[i] == 0) {
cout << "I suppose you're entitled to change your mind.\n";
}
else if (quantityOfDish[i] < 0) {
cout << "Your generosity is appreciated but I must decline!\n";
quantityOfDish[i] = 0;
}
i++;
}
else if (userResponse == 'n' || 'N')
{
i++;
}
else
{
cout << "I think you mumbled NO, so I'll just go on.\n";
i++;
}
}
Is there any particular reason why despite inputting 'n' it still goes into the 'Y' if conditional block?
I have stepped through the code in the debugger, and I noticed that the userResponse variable is being read in properly. Yet, the if condition does not seem to be working properly. Thanks!

Answer 1

This statement (and your other if statement) is not doing what you think it does:
if (userResponse == 'n' || 'N')
Try this instead:
if (userResponse == 'n' || userResponse =='N')

Answer 2

You need to define each logical operation individually in a condition check. You will have to compare userResponse with n and N separately.
if (userResponse == 'y' || userResponse == 'Y')
{
cout << "How many orders of " << nameOfDish[i] << " would you like?\n";
cin >> quantityOfDish[i];
if (quantityOfDish[i] == 0) {
cout << "I suppose you're entitled to change your mind.\n";
}
else if (quantityOfDish[i] < 0) {
cout << "Your generosity is appreciated but I must decline!\n";
quantityOfDish[i] = 0;
}
i++;
}

Answer 3

It's been awhile since I worked in C++, but I'm fairly sure I know what's going on.
The || operator does not work on a single conditional, there must be two complete conditionals, one on each side. Try replacing your if statement with this line:
if (userResponse == 'y' || userResponse == 'Y')

Answer 4

Maybe you are used to SQL? You need to repeat the userResponse
if userResponse == 'n' || userResponse == 'N'
Otherwise you are actually testing
if userResponse is 'n' or the char'N' exists

Answer 5

The error in this code is, as others have pointed out, the if statement. However, I feel this may need some clarification. Every C++ expression returns a value. For example.
userResponse == 'y'
returns the value 1 if userResponse is 'y' and 0 if it is anything else. The operator || returns 1 if either the left or the right expression is non-zero.
Finally, the if statement checks to see whether or not the expression is zero or non-zero. So,
if (5)
cout << "X";
else
cout << "Y";
will print X and
if (0)
cout << "A";
else
cout << "B";
will print B.
Now, we can begin to understand why your code compiled successfully, but didn't do what you wanted it to.
if (userResponse == 'y' || 'Y')
In this example, the || operator will always return 1 because the expression on the right, 'Y', will always be non-zero (specifically, it will be 89, since C++ characters are just aliases for their ASCII corresponding number). And of course,
if (userResponse == 'y' || userResponse == 'Y')
work as intended. But there is a much better solution and that would be the switch statement, whose purpose is to handle situations like this. Here it is in action:
switch (userResponse) {
case 'y':
case 'Y':
//The user answered yes, handle that situation here.
break;
case 'n':
case 'N':
//The user answered no, handle that situation here.
break;
default:
// The user did not enter a valid answer,
// handle that situation here.
break;
}