Control Structures

Terminology

⟹ Flow of Control =  which statement gets executed next? A.k.a., logic flow.

⟹ Control Structures = statements which control logic flow

⟹ Three Categories of Control Structures:

1. Sequence (from the top to the bottom, in order)
2. Selection (if statement)
3. Iteration (while, for, and do-while loops)

Examples

• Meet the Loops (modern javascript tutorial)
• Flip a coin. Rewrite using a do-while loop.

Optional Loop Practice

The peasant multiplication algorithm (PMA) is an ancient system for multiplying two numbers. It requires only the ability to double, divide by 2, and add.

Exercise: Translate this pseudocode Peasant Multiplication Algorithm (PMA) into a JavaScript function named pma that accepts two numbers and returns their product.

//pseudocode notation-- this is not JavaScript
Begin PMA

    var i = 7, j = 10, prod = 0;
    
    while(i not equal 0)
        if(i is odd)
            answer = answer + j
        divide i by 2, and discard remainder
        double j
        
    display i, j, answer

End PMA.