Pig Latin - strings - c++

Question

So I am supposed to convert English words to Pig Latin using stringConvertToPigLatin(string word) function. All the answers I could find on the internet were using char[], and I am not allowed to do so.
The program is supposed to begin with adding -way if the first letter is a vowel, and adding -ay if it's a consonant. The problem is that it is always adding "-way", even if my "word" has no vowel at all. What am I doing wrong? This is my function:
string ConvertToPigLatin(string word)
{
char first = word.at(0);
cout << first << endl;
if (first == 'a' || 'A' || 'e' || 'E' || 'i' || 'I' || 'o' || 'O' || 'u' || 'U')
{
word.append("-way");
}
else
{
word.append("-ay");
}
return word;
}

Answer 1

As noted in the comments your if statement is wrong. Each comparison needs to be done individually. From the comment.
if (first == 'a' || first == 'A' || first == 'e' || ...)
However, rather than using a long if statement you should consider stuffing all of the vowels into a string and using find. Something like the code below will be easier to read and follow.
#include <iostream>
#include <string>
std::string ConvertToPigLatin(std::string word)
{
static const std::string vowels("aAeEiIoOuU");
char first = word.at(0);
std::cout << first << std::endl;
if (vowels.find(first) != std::string::npos)
{
word.append("-way");
}
else
{
word.append("-ay");
}
return word;
}
int main()
{
std::cout << ConvertToPigLatin("pig") << '\n';
std::cout << ConvertToPigLatin("alone") << '\n';
}
This outputs
p
pig-ay
a
alone-way

Answer 2

I'll explain why your code isn't working:
if (first == 'a' || 'A' || 'e' || 'E' || 'i' || 'I' || 'o' || 'O' || 'u' || 'U')
Let's walk through that iff statement using the word "Pig"
First the program checks first == 'a'... first == 'P' so that is false.
Then the program checks to see if false || 'A' is true. Since 'A' is true, false || 'A' is also true.
Short circuit evaluation kicks in, and the code doesn't bother checking the rest of the statement, the if condition is true so -way is appended.
To do what you want, you need to compare first to each letter. I.E.,
if (first == 'a' || first == 'A' || ...
Don't worry too much, this is a pretty standard mistake.