Structured program theorem

The Structured Programming Theorem says that any imperative program need the following control statements only:

1. Assignment statement,
2. a sequence of statements,
3. an If-Then and If-Then-Else statement,
4. and a While statement.

There does not need to be a 'goto' statement. It leads to "spaghetti code", since you can jump all over the place.

(this article is a stub written by a total beginner...)