1 st Semester Module4-1 Iteration statement - while อภิรักษ์ จันทร์สร้าง Aphirak Jansang Computer Engineering Department Kasetsart University, Bangkok THAILAND

1 st Semester /39 Outline  Review condition statement  Loop statements while statement do…while statement for statement  break statement

1 st Semester /39 Simple C# Structure  Namespace Class  Main()Namespace Class Main() Variable & Constant Location statements WriteLine, ReadLine, if, switch, Loop Review condition statement

1 st Semester /39 Condition Statements condition if (condition) statement; condition if (condition) statement1; else statement2; ( ) switch ( ) { case : ; break; default: ; break; } Review condition statement

1 st Semester /39 Outline  Review condition statement  Loop statements while statement do…while statement for statement  break statement

1 st Semester /39 Loop or Iteration in C# for while do…while foreach Iteration Loop statements

1 st Semester /39 C# Program with Condition Start statement1 statement2 statement3statement4 End Condition true false Loop statements

1 st Semester /39 Simple C# Program Start statement1 End statement1 Loop statements

1 st Semester /39 Simple C# Program with Loop Start x=5; statement1 x=x-1; End x>0 true false Loop statements

1 st Semester /39 Outline  Review condition statement  Loop statements while statement do…while statement for statement  break statement

1 st Semester /39 while statement condition statement true false while (condition) statement; while statement

1 st Semester /39 while statement – more statements while (condition) { statement1; statement2; } condition statement1 true false statement2 while statement

1 st Semester /39 Example1: while statement  2 n = ???  n = 5 result=2*2*2*2*2 = 32 result=2*2*2*2*2 = 32 result=1; result = result*2; n=n-1; n>0 true false n=5; Display result See demo program!!!! prog2-loop.cs while statement

1 st Semester /39 Example2: while statement  n = 5 result = result = result=0; result = result+n; n=n-1; n>0 true false n=5; Display result See demo program!!!! prog3-loop.cs while statement

1 st Semester /39 Iteration Template  Counter Controlled  Sentinel Controlled while statement

1 st Semester /39 Counter Controlled  Control Variable – counter variable  Three component Initial counter variable condition (counter variable is still valid?) Incrementing/Decrementing counter variable while statement: counter controlled

1 st Semester /39 Example3: Count Controlled  Display 1 – 7 on screen initial counter statement; dec||inc counter condition true false See demo program!!!! prog4-loop.cs while statement: counter controlled

1 st Semester /39 Break!!!! (5 minutes) (Elevator) Neo: There is no spoon... there's a difference between knowing the path and walking the path... Morpheus: Neo, sooner or later you're going to realize, just as I did, there's a difference between knowing the path and walking the path... Trinity: Run, Neo. Run! What is he doing? Morpheus: He's beginning to believe * From The Matrix

1 st Semester /39 Iteration Template  Counter Controlled  Sentinel Controlled while statement

1 st Semester /39 Sentinel Controlled  Input driven program  #repetition cannot tell  depend on condition and input  Sentinel Value Causes loop to break while statement: sentinel controlled

1 st Semester /39 Example4: Sentinel Controlled  Find summation from user input  Exit program when user input negative number See demo program!!!! prog5-loop.cs while statement: sentinel controlled

1 st Semester /39 Break 3 Minutes “With great power comes with great responsibility” *From Spiderman

1 st Semester /39 Example 5: Display n stars See demo program!!!! prog6-loop.cs while statement: example

1 st Semester /39 Example 6: Display stars See demo!!!! prog7-loop.cs while statement: example

1 st Semester /39 Example 7: Display stars See demo!!!! prog8-loop.cs while statement: example

1 st Semester /39 Example 8: Display stars See demo!!!! prog9-loop.cs while statement: example

1 st Semester /39 Summary  Loop statements while statement do…while statement for statement  break statement