If the condition evaluates to FALSE or NULL, the loop is bypassed, and control passes to the next statement.
如果条件的求值结果为FALSE或NULL，那么将绕过循环，并且控制被传递给下一条语句。
2
If the condition evaluates to TRUE, the statement list is executed, then control resumes at the top of the loop.
如果条件的求值结果为TRUE，那么就将执行语句列表，在循环的顶部恢复控制。
3
The GOTO label statement can unconditionally exit from a loop and transfer control to the executable statement or statement block that follows the specified statement label.
GO TO标签语句可以无条件地退出循环，并将控制权转移到跟在指定的语句标签之后的可执行语句或语句块。