Andy hughes is spot on, but if i may add that Anka wrote the english lyrics to a french ballad originally called 'comme d'habitude' ( same as usual )that he heard Claude Francois singing in 1968. Not certain if CF actually wrote it but think it is highly likely as he was a prolific singer/songwriter in his own right. Cheers
Claude Francois co-wrote Comme d'habitude in 1967, he died on March 11th 1978 changing a lightbulb whilst still in the bath. Check out www.cloclo39.2itb.com which is an English version of his life story