A pickup code has to match character for character before the item is released. Compare entered and issued with strcmp(...) == 0. Comparing their addresses with == would not tell you whether the text matches.
entered with issued using strcmp; print Release item when they match, or Ask for code otherwise. Keep the supplied strings unchanged for submission, producing exactly Release item and a newline.As a second check, change a single character locally and confirm the other branch, then restore it.
strcmp returns zero when the character sequences are equal.