Summary judgment if the statement

1, the expression: Relationship between expression or logical expressions;

2, the expression of the result of the operation should be "true" or "false" ;

      True: the implementation of the statement;

           False: Skip the statement, the next statement;

3, "the statement" can be a single statement may also be a compound statement ;

4, the else IF  you can have multiple, there is no upper limit;

. 5, if required, and determines expression else if true and false, else it is not necessary, and if else if else must be used together with, can not be used alone.