The document provides an overview of control statements in C#, including selection structures like if and switch, as well as repetition structures like while loops. It explains various programming techniques such as controlled entry and exit from modules, avoiding goto statements, and using nested ifs for conditional logic. Additionally, it covers type conversion, particularly in arithmetic operations, and offers examples for implementing these concepts in C#.

1. C#
Control Statements
PF 102

2. Control statements
Linear (sequential) program execution
Selection structure and repetition structure
Structured programming
◦ Controlled entry and exit out of a module.
◦ Avoid goto statements

3. Selection structures in C#
if
 single selection statement
if…else
double selection statement
switch
multiple – selection statement

4. Examples:
if (grade >= 60)
Console.writeline(“Passed!”);
If (grade >=0)
Console.writeline(“Passed!”);
else
Console.writeline(“Failed!”);
Conditional Operator
Console.writeline(grade >= 60 ?“Passed!” : “Failed!”);

5. Nested
if (grade >=90)
Console.writeline(“A”);
else if (grade >=80)
Console.writeline(“B!”);
…
else
Console.writeline(“F!”);

6. Repetiton Structure - while
While (condition){
statement 1;
statement 2;
statement 3;
…
}

7. Example
length = Convert.ToInt16(Console.ReadLine());
while (length > 0)
{
Console.Write("Enter Height of the Wall: ");
height = Convert.ToInt16(Console.ReadLine());
PaintAWall thisWall = new PaintAWall(length, height, pricePerGal);
thisWall.CalculateCost(ref paintCost,ref laborCost,ref galPaint, ref sqFt);
Console.Write("Enter Length and Height for Wall # : “ +
Convert.ToString(numWalls+1));
Console.Write("nEnter Length of the Wall (0 to quit): ");
length = Convert.ToInt16(Console.ReadLine());
}

8. Counter controlled vs
Sentinel controlled
A while loop, use LCV as a counter
Counter =1
While (counter <=10)
{
…
Counter ++
}//does it 10 times
Sentinel controlled is good when one does not know exact number of
times to execute a loop

9. Explicitly and Implicitly converting
between simple types
Integer and integer division yields integer result.
Suppose average is a floating point number:
Average = total/num. Average will only get an integer if
total and num are integers.
int sum = 200, num = 3;
float average;
average = sum / num;
Console.WriteLine(average);
Will print 66

10. Unary Cast Operator
int sum = 200, num = 3;
float av;
av = (float) sum / num;
Console.WriteLine(av);
Will print 66.6666
Float/float or float/int or int/float will yield a float.
C# implicitly promotes the one int to float.

11. Nested control statements
See example of a multiplication table generation
class MultiplicationTable{
static void Main(string[] args){
int i=2, j, k;
while (i <= 12){
for (j = 1; j <= 10; j++){
Console.WriteLine(i + " x " + j + " = " + i * j );
}
Console.WriteLine("n");
i++;
}
}
}
}

12. Switch Statements
Switch (expression) {
case value1: //Statements
break;
case value 2: //Statements
break;
case value 3: //Statements
case value n: //Statements
break;
default: //Statements
}