Lesson 3. Controlling program flow. Loops. Methods. Arrays. Programming in C# Lesson 3. Controlling program flow. Loops. Methods. Arrays.

Three types of program flow Straight line Chosen depending on a given condition Repeated according to a given condition

Making decisions

Making decisions in UML diagram

Two main constructions to control program flow IF/ELSE SWITCH

IF/ELSE construction if (condition) statement or block we do if the condition is true else statement or block we do if the condition is false

Conditions and Relational Operators == > < <= >= != ! Only two types of values: true or false

Combining Logical Operators && ||

Combining Logical Operators sample:

Combining Logical Operators inversed sample:

SWITCH construction switch (value) { } case ‘option 1’: statement or block we do if value equals ‘option 1’ break; case ‘option 2’: statement or block we do if value equals ‘option 2’ case ‘option 3’: statement or block we do if value equals ‘option 3’ default: statement or block we do in all other cases }

Loops

Loops in UML diagram

Four main types of loops DO-WHILE WHILE FOR FOREACH

DO-WHILE Loop do statement or block while (condition);

DO-WHILE Loop Sample

WHILE Loop while (condition) statement or block

WHILE Loop Sample

FOR Loop for (setup; finish test; update) things we want to do a given number of times

FOR Loop Sample

Breaking Out of Loops break continue

Methods Reusing a piece of code Break down a large task into a number of smaller ones

Simple method sample

Method Parameters

Method Parameters

Method Signature Type of Parameters Number of Parameters Return Type

Parameter Passing By Value

Parameter Passing By Reference

Passing Parameters as “out” Reference

What else should we know about method parameters? Default parameters Variable number of parameters Method overload

Arrays

Array declaration

Array in Memory

Array Elements

Array Elements Initialization

Managing Array Sizes

Two Dimensional Arrays

Two Dimensional Array Declaration

Arrays and Lookup Tables