Switch statements

if(expression == value1) {
  // more statements;
  .....
}
else if(expression == value2) {
  // more statements;
  .....
}
else {
  // more statements;
  .....
}

switch (expression) {          
  case value1 :
  // more statements;
    .....
    break;

  case value2 :
    // more statements;
    .....
    break;

  default :
    // more statements;
    .....
    break;
}

switch (expression) {
  case value1 :
  case value2 :
    // handle either value1 or value2
    .....
    break;

  case value3 :
    // more statements;
    .....
    // no 'break' statement, drop through

  default :
    // more statements;
    .....
    break;

}

• Typically the 'expression' is simply an identifier, but it may be arbitrarily complex - such as an arithmetic expression, or a function call.
• The datatype of the 'expression' must be an integer (which includes characters, Booleans, and enumerated types), but it cannot be a real or floating-point datatype.
• The break statement at the end of each case indicates that we have finished with the 'current' value, and control-flow leaves the switch statement.
  Without a break statement, control-flow continues "downwards", flowing into the next case branch (even though the expression does not have that case's value!).
• switch statements with 'dense' values (none, or few integer missing) provide good opportunities for optimised code.
• There is no need to introduce a new block, with curly-brackets, unless you need to define new local variables for specific case branches.