3.Control Structures

1. Sequential Control Structures

                - program statements are executed from top to bottom.

            Example:

sum=number1+number2;

average=sum/2;

Console.WriteLine("Sum="+sum);

Console.WriteLine("Average="+average);

2. Decision Control Structures

            - allows selection of specific sections of code to be executed.

1.   Simple

int score=30;

if(score<75){

Console.WriteLine("Failed");

}

else{

Console.WriteLine("Passed");

}

2.   Nested

int score=30;

if(score<75){

      Console.WriteLine("Failed");

}

else if (score<85){

      Console.WriteLine("Average");

}

else if (score<90){

      Console.WriteLine("Above Average");

}

else{

      Console.WriteLine("Excellent")

}

3.   Complex

if(score<75){

      if(….){}else{…}

else if (score<85){

       if(….){}else{…}

}

else if (score<90){

       if(….){}else{…}

}

else{

       if(….){}else{…}

}

             -  2 types of decision control structures

1.       Sequential if

2.       Nested if

3. Repetition Control Structures

 - allows the repetition of an action while some condition remains true.

o   do..while loop

example1

do{

                        Console.Write("Try Again[y/n]?: ");

                        tryAgain=char.Parse(Console.ReadLine());

  }while(tryAgain=='y');

example2

 do{

       ctr++;

    }while (ctr<=10);

o   while loop

example1

char  tryAgain='y';

            while(tryAgain=='y'){

                        Console.Write("Try Again[y/n]?: ");

                        tryAgain=char.Parse(Console.ReadLine());

            }            

 example2

int ctr=0;

while(ctr<=10){

       ctr++;

}

o   for loop

 for (int ndx = 0; ndx < 10; ndx++) {   

      Console.WriteLine (ndx);

}

   -  2 types of repetition control structures

     1.       Sentinel loop

     2.       Counting loop