Two-way Selection: if-else Statements

Introduction: 3.3.0

• use if and else to pick between two possibilities
• Can be used with relational operators

boolean myExpr = false;
if (myExpr) {
  doSomethingWhenTrue();
} else {
  doSomethingWhenFalse();
}

Nested ifs and Dangling else: 3.3.1

• if statements can be nested
• Can sometimes have “dangling else” which could belong to either
  • This always belongs to the closest if statement
    • Regardless of Indentation
  • Use curly brackets to differentiate

if (boolean)
  if (boolean)
    doSomething();
else // THIS BELONGS TO THE SECOND IF

if (boolean) {
  if (boolean)
    doSomething();
} else {
// BELONGS TO THE SECOND IF
}

Summary: 3.3.3

• if statements can be followed by an else to make a 2-way branch
  • One executed when true, the other when false
• Use 2 test-cases to test both branches and fine errors
• else statements attach to the nearest if