Array and loops

[DragoraGamer]

Hello I'm new to this forum and C++. I'm trying to write a program that reads input from a user and in a loop prints out only the vowels of that word. If possible may I know in simplest terms? Thanks.

#include <iostream>

using namespace std;

int main()
{
char array[30];
char vowel[6] = { 'a', 'e', 'i', 'o', 'u',};

for( int i = 0; i < 30; ++i )
{
array[ i ] = '\0';
}
cin.get(array , 30);

for ( int i = 0; i < 30; i++)
{
for ( int j = 0; j < 6; j++)
{
if (vowel[i])
{
cout << vowel[i] << " ";
}
}
}
system("Pause");
return 0;
}

I tried array[i] == vowel[j] in a for loop but, it says i and j are not initialized.

[Cubbi]

Why are you trying to use arrays if you're receiving strings from the user?

In modern C++, this program could look more like

#include <iostream>
#include <string>
#include <set>
const std::set<char> vowels = {'a', 'e', 'i', 'o', 'u'};
int main()
{
    std::string line;
    getline(std::cin, line);
    for(char c: line)
        if(vowels.count(c))
            std::cout << c << " ";
    std::cout << '\n';
}

With an older compiler, you could use something like

#include <iostream>
#include <string>
const std::string vowels = "aeiou";
int main()
{
    std::string line;
    getline(std::cin, line);
    for(size_t i = 0; i < line.size(); ++i)
        if(vowels.find(line[i]) != std::string::npos)
            std::cout << line[i] << " ";
    std::cout << '\n';
}

online demo: http://ideone.com/zzb7h

Although it would be better style if you wrote a function isvowel() that takes a char and returns a bool.

[DragoraGamer]

erm it's because I have not learned of functions yet. and the excercise I recieved says to make a program out of loops and arrays. Like being limited to see if I fully understand all that has been discussed so far. Thanks though.

[Cubbi]

someone's teaching you C in a C++ class, that's rather discouraging to hear.

but anyway, your idea of using array[i] == vowel[j] was sound.

try your program with the following inner loop:

       for ( int j = 0; j < 5; ++j)
        {
            if (array[i] == vowel[j])
            {
                cout << array[i] << " ";
            }
        }

online demo: http://ideone.com/v6Z1z

[DragoraGamer]

Thanks alot! this really helped and solved my problem.