Control Structures: Selection (Conditional Expressions)

• The ? : operator
  
• Allows the building of a new expression using three other expresssions
  expression_1 ? expression_2 : expression_3
• Either expression_2 or expression_3 is evaluated depending
  on the truth value of expression_1
• False is represented by a 0 value and true by any non-zero value
• For example, the following returns the larger of two values:
  return(a < b ? b : a)
• 
  
  • The if statement
  • Form 1: if (expression) statement_1
  • Form 2: if (expression) statement_1; else statement_2
  • Blocks of statements (compound statements) may also be used
  • The logical &&, || operators can be used to evaluate multiple expressions in the if statement
  • if statements may also be nested
  • Example...

  
  

  • The switch statement
  • Syntax:
    

    switch (expression)
    {
    	case constant1: {statement ... statement}
    	case constant2: {statement ... statement}
    	...
    	default: {statement ... statement}
    }

  • No variable is allowed in the constant expression to the left of the colon
  • The constant prefix may occur more than once before a sequence of statements
  • The break statement is used to jump out of a switch block
  • Example of a switch statement...