1. The University of Texas Rio Grande Valley
CSCI 3328 Object Oriented Programming in C# Chapter 5: C# Control Statement – Part II
Xiang Lian
The University of Texas Rio Grande Valley
Edinburg, TX 78539
This set of slides is revised from lecture slides of Prof. John Abraham. -- Xiang Lian

2. Objectives In this chapter, you will: Learn more control structures
Repetition statements
for, do … while
Selection
switch
Know how to use break and continue statements to terminate the loop or current iteration
Learn how to use logical operators in C#

3. Repetition Structure Visual C# provides 3 repetition statements while
for
do … while

4. In the Last Class: Counter Controlled while Loop
int Counter =1;
while (Counter <=10) { …
Counter ++;
}//does it 10 times

5. Example of for Repetition Statement
Output even numbers between 2 and 10
for (int counter = 2; counter<= 10; counter+=2) {
Console.Write("{0} ", counter);
Console. WriteLine(); }

6. Discussions on for Repetition Statement
for (int counter = 2; counter <= 10; counter += 2)
Keywords: for
"int counter" declares a counter of integer data type
counter – control variable name
int – control variable type
Initial value of control variable – 2
Final value of control variable – 10

7. General Form of a for Statement
for (initialization; loopContinuationCondition; increment) {
statement }

8. Other Examples of for Statement (1)
Declaring the control variable before a for statement
int counter;
for (counter = 2; counter <= 10; counter+=2)
Console.Write("{0} ", counter);
Using expressions in the for statement
for (counter = x; counter <= 4*x*y; counter+=y/x)

9. Other Examples of for Statement (2)
Increment: 1
for (counter = 2; counter <= 10; counter++)
Decrement
for (counter = 10; counter >= 2; counter-=2)

10. Example of Interest String.Format("{0, 20}", "...");
decimal amount; decimal principal = 1000; double rate = 0.05; Console.WriteLine("Year{0, 20}", "Amount on deposit"); for (int year = 1; year <= 10; year++) { amount = principal *((decimal)Math.Pow(1.0+rate, year)); }
field width
String.Format("{0, 20}", "...");

11. do…while Repetition Statements
The loop body is always executed at least once
int product = 1; do {
product = product * 3;
}while (product <=100);

12. Use break to Terminate Repetition Statements
for (int counter = 1; counter <=10; counter ++) { if (counter == 5) break; Console.Write("{0} ", counter); } // answer:

13. Use continue to Terminate the Current Iteration
for (int counter = 1; counter <=10; counter ++) { if (counter == 5) continue; Console.Write("{0} ", counter); } // answer:

14. In the Last Class: Selection Structures in C#
if – single selection statement
if … else – double selection statement
switch – multiple selection statement
[grade>=60]
display "passed"
[grade<60]

15. Example of Multiple Selection Statement
public void CalculateGrade(int grade) { switch (grade/10) case 9: // case 10: // 100 Console.WriteLine("Grade: A"); break; case 8: Console.WriteLine("Grade: B"); break; // case 7: Console.WriteLine("Grade: C"); break; // case 6: Console.WriteLine("Grade: D"); break; // default: Console.WriteLine("Grade: F"); break; // < 60 }

16. Expression 1 && Expression 2
Logical Operators
Conditional AND operator (&&)
if (gender == 'F' && age >=65)
seniorFemales += 1;
Expression 1
Expression 2
Expression 1 && Expression 2
false
true

17. Logical Operators (cont'd)
Conditional OR operator (||)
Expression 1
Expression 2
Expression 1 || Expression 2
false
true

18. Short-Circuit Evaluation
Conditional AND operator (&&)
if (gender == 'F' && age >=65)
If gender is not "F", then "age >=65" will not be evaluated
Conditional OR operator (||)
if (gender == 'F' || age >=65)
If gender is "F", then "age >=65" will not be evalutated

19. Boolean Logical Operators
Boolean Logical AND ( & )
if (gender == 'F' & age >=65)
No matter what value gender has, “age>=65” will always be evaluated
Boolean Logical OR ( | )
Logical Negative ( ! )

20. Other Boolean Logical Operators
Boolean Logical Exclusive OR (^)
If both conditions are the same, then output is false
Expression 1
Expression 2
Expression 1 ^ Expression 2
False
True