Algorithm learning at "Women who code" class

piglatin.cpp

#include<iostream>
#include<string>

using std::cout;
using std::string;
using std::cin;
using std::endl;


string piglatin(string word){
    if(word.size() == 0){
        return "Empty string";
    }
    else{
    if((word[0] == 'b')||
       (word[0] == 'c')||
       (word[0] == 'd')||
       (word[0] == 'f')||
       (word[0] == 'g')||
       (word[0] == 'h')||
       (word[0] == 'j')||
       (word[0] == 'k')||
       (word[0] == 'l')||
       (word[0] == 'm')||
       (word[0] == 'n')||
       (word[0] == 'p')||
       (word[0] == 'q')||
       (word[0] == 'r')||
       (word[0] == 's')||
       (word[0] == 't')||
       (word[0] == 'w')||
       (word[0] == 'v')||
       (word[0] == 'x')||
       (word[0] == 'z')){
         char tmp = word[0];
         int word_length = word.size();
         int i=0;
         for(i=0; i != word_length-1; i++){
            word[i] = word[i+1];
         }
         word[i] = tmp;
         word = word + "ay";
    }
    else{
        return "Wrong word";
    }
    return word;
    }
}

int unit_test(){

    string test;

    test = "";
    cout << "Empty string test: " << piglatin(test) << endl;

    test = "apple";
    cout << "Test word is \"" << test << "\": " << piglatin(test) << endl;

    test = "banana";
    cout << "Test word is \"" << test << "\": " << piglatin(test) << endl;
}

int main(){

    unit_test();

    return 0;
}