Conditional and Relational Operators/Statements

Nota:

• Learn these: < (less than), >(greater than), ==(equal to), <=(less than/equal to), >=(greater than/equal to), !=(does not equal) See more: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op2.html

1. Conditional Operators

   Nota:

   • Learn These: &&(and), ||(or)
   1. De Morgan's Law

      Nota:

      • De Morgan's Law: !A && !B == !(A || B); !A || !B == !(A && B); Find more info here: http://fcmail.aisd.net/~JABEL/1DeMorgansLaw.htm
2. Conditional Statements

   Nota:

   • If/then statements switch statements See more: https://www.inf.unibz.it/~calvanese/teaching/04-05-ip/lecture-notes/uni05.pdf
   1. If/Then statements

      Nota:

      • Syntax: if(condition){     statements } see more: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/if.html
      1. Multiple else/if

         Nota:

         • syntax: if(condition){    statements; } else if(condition){    statements; } ... //as many as you need else{ statements; }
      2. nested if statement

         Nota:

         • Nested if statements are if statements within if statements. There also can be else statements within these. Pair up the ifs and else's by having the pair closest line up if they are in the same brackets. Try starting with the inner ifs Then pair the outer ones. Ex: if(condition){ //pairs with last    if(condition){ //pairs with 1st    }    else{ //1st else     } } else{ //last else } see more: https://www.cs.umd.edu/~clin/MoreJava/ControlFlow/nested-if.html
   2. Switch Statements

      Nota:

      • syntax: switch(variable){     case value: statements;                           break; //optional     ... } see more: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
      1. Valid data types

         Nota:

         • You can use a byte, short, char, int or String(Java 7+ only). You can also use other "wrapper" classes that hold these values, such as Character, Byte, Short, Integer. These will be used later in the year. See more: https://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
      2. Case Groups

         Nota:

         • if there is no statements after a case, the next statements after a case will be used instead. This means multiple conditions can be used for the same statement. Example: int test = 2; switch(test){ case 1: case 2: case 3: System.out.println("test < 4"); break; case 4: case 5: System.out.println("test >3"); break; } This shows how multiple values can be used for one statement within a switch. For another example, look toward the bottom of this page: http://www.dummies.com/how-to/content/switch-statements-in-java.html    
         1. Break

            Nota:

            • break within a switch statement exits the rest of the switch statement once hit. Without a break in a switch, it will keep running through the cases even if another has already been activated. Here's an example of when it would be useful to include a break: http://stackoverflow.com/questions/2710300/why-do-we-need-break-after-case-statements
      3. Default

         Nota:

         • "case default:" is used at the end of a switch and always runs at the end if the switch hasn't broken. It is usually used to let the user know that the variable tested didn't meet any of the case values. See here for explanations and a small exersice: http://www.homeandlearn.co.uk/java/java_switch_statements.html