loosing the first element of an array

[ToeMater]

I call this function to assign a MyString object to another but I end up losing the first value somehow.

If you need some other part of the code here is a GitHub repo
https://github.com/MarkFuller1/Project_1.5

  MyString &MyString::operator=(const MyString &input) {
    
    while (input.data[++charCount] != '\0') {
        if (charCount >= this->capacity) {
            auto *temp = new char[this->capacity * 2];
            this->capacity *= 2;
            for (int j = 0; j < charCount; j++) {
                temp[j - 1] = this->data[j];
            }
            delete[] this->data;
            this->data = temp;
        }
        this->data[charCount] = input.data[charCount];
    }

    size = charCount;

    return *this;
}

[ToeMater]

SOLVED: line 8, temp[j - i] should be just temp[j]