I'm having a weird problem with the following function, which returns a string with all the characters in it after a certain point:

string after(int after, string word) {
    char temp[word.size() - after];
    cout << word.size() - after << endl; //output here is as expected
    for(int a = 0; a < (word.size() - after); a++) {
        cout << word[a + after]; //and so is this
        temp[a] = word[a + after];
        cout << temp[a]; //and this
    }
    cout << endl << temp << endl; //but output here does not always match what I want
    string returnString = temp;
    return returnString;
}

The thing is, when the returned string is 7 chars or less, it works just as expected. When the returned string is 8 chars or more, then it starts spewing nonsense at the end of the expected output. For example, the lines

cout << after(1, "12345678") << endl;
cout << after(1, "123456789") << endl;

gives an output of:

7
22334455667788
2345678
2345678
8
2233445566778899
23456789?,?D~
23456789?,?D~

What can I do to fix this error, and are there any default C++ functions that can do this for me?