while statement

Map Branches

• loops
  • while statement
    • Syntax
      • while ( expression ) statement
      • Driving Factors
        • Before the Loop
          • Initialization
        • In the Loop
          • Modification
            • value that affects the loops expression
              • Within expression
                • while ( ++variable ) statement
              • After expression
                • while ( expression ) ........ ........ ++variable
            • Counter
              • Variable
                • Holds Value of # of loops
          • Termination
            • causes loop to terminte
              • a condition
    • purpose
      • repeated execution of a statement or statement block
        • as long as expression is true
  • for statement
    • syntax
      • for ( expression1 ; expression2 ; expression3 ) statement
      • Initialization
        • expression1
          • evaluated once - beginning
      • Termination
        • expression2
          • evaluated each time - beginning
      • Modification
        • expression3
          • evaluated each time - bottom - post statement execution
      • infinite loop
        • for ( ; ; ) DoSomethingForever()
          • no initialization, termination, and modification
            • considered bad form
    • comparison
      • for loop as while loop
        • expression1; while ( expression2 ) { statement expression3; }
          • for loop and while loop are interchangable
  • do statement
    • syntax
      • do statement while ( expression ) ;
    • comparison
      • unlike while and for loop
        • expression is evaluated at the bottom of loop
          • consequence of bottom evaluation
            • loop statement always executed at least once
• selection statements
  • if statement
    • Types
      • Regular (no else)
        • Syntax
          • if (expression) statement
          • Statements are executed/triggered only if expression evaluates to "not false"
      • If with else
        • Syntax
          • if ( expression ) statement else statement
            • if expression = not false
              • execute statements after expression and ignore statements after else
            • if expression = false
              • execute statements after else
    • Value
      • "If statement expressions" can evaluate to false or not false
        • false and not false have values
          • If the expression evaluates to 0
            • expression is false
              • If Statment is not triggered
          • If expression does not evaluate to 0
            • expression is not false
              • If Statement is triggered
    • Purpose
      • One time execution of a statement or statement block
        • based on value of expression
  • switch statement
    • syntax
      • switch ( expression ) { case value1: statement break; case value2: statement break; case valueX: statement break; default: statement }
        • case value has to be constant or single-byte characters
        • case value cannot be a variable or mutiple-byte character strings
    • purpose
      • uses value of expression to determine which case is executed
    • case with no statements
      • used to make two cases execute the same statement
        • switch ( numberOfEggs ) { case 1: case 2: HardBoilThem(); break; case 3: MakeAnOmelet(); default: }
          • case 1 and 2 will execute the same statement - break is missing in case 1
    • break statement and fall-through
      • not adding breaks in the cases
        • adds more functionality as you fall-through the cases
          • switch ( myVar ) { case 1: DoSometimes(); case 2: DoFrequently(); default: DoAlways(); }
            • if myVar is case1 all functions get executed
            • if myVar is case2 then functions in this case and default get executed
            • if myVar case is not 1 or 2 then function after default get executed

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