How do you prevent your children from cursing?

We should ourselves not curse in front of them or otherwise. But I have seen kids whose parents do not use foul words but kids happen to speak bad words and it has happened in my case as well, and the culprit was a cartoon series on the television. So, one must check what the child is watching. And as far as kid hearing bad words in the outside environment, the you must tell your child that it is very bad to talk in such language and can educate the child depending what is the child's age.