C# Syntax and Output

1. C# Syntax and Output Lab 0A

2. A bare bones class! public class CompSci { } All C# programs start with a class.

3. bare bones + a Main! public class CompSci { public static void Main(String[] args) { Console.WriteLine("Comp Sci!"); } } OUTPUT Comp Sci!

4. syntax rules public class CompSci { //open brace public static void Main(String[] args) { Console.WriteLine ("Comp Sci!"); } } //close brace Braces – You gotta have ‘em! Every class and every method must have a { and a } .

5. syntax rules public class CompSci { public static void main(String[] args) { Console.WriteLine("Comp Sci!"); } } You must put a semi-colon at the end of all C# program statements ( ; ).

6. { and ; rule Never put a ; before an open { brace ;{ //illegal }; //legal

7. indentation public class CompSci { public static void Main(String[] args) { Console.WriteLine("Comp Sci!"); } } Indent all code 3 spaces to make it easier to read. 123

8. C# Output

10. C# Output reference command / method Console.Write("compsci"); OUTPUT compsci

11. C# Output Console.Write("compsci"); Console.Write("compsci"); OUTPUT compscicompsci

12. C# Output Console.WriteLine("compsci"); OUTPUT compsci

13. C# Output Console.WriteLine("compsci"); Console.WriteLine("compsci"); OUTPUT compscicompsci

14. C# Output Escape Sequences \n newline \t tab \r carriage return \b backspace Console.WriteLine("c\tompsci"); OUTPUT c ompsci

15. C# Output Escape Sequences \n newline \t tab \r carriage return \b backspace Console.WriteLine("com\tpsci"); OUTPUT com psci

16. C# Output Escape Sequences \n newline \t tab \r carriage return \b backspace Console.WriteLine("comp\nsci"); OUTPUT compsci

17. C# Output Escape Sequences \\ outs \ \" outs " \’ outs ’ Console.WriteLine("\\compsci\"/"); OUTPUT \compsci"/

18. C# Output Escape Sequences \\ outs \ \" outs " \’ outs ’ Console.WriteLine("\\'comp\'sci\'/"); OUTPUT \'comp'sci'/

20. C# Comments // single-line comments /* */ block comments //this line prints stuff on the screen Console.WriteLine("stuff");

21. C# Comments // single-line comments /* */ block comments /* this line prints stuff on the screen */ Console.WriteLine("stuff");

22. Errors Syntax errors occur when you type something in wrong, causing the code to not compile. //missing semicolon - ; expected Console.WriteLine("stuff") //case problem – should be System Console.WriteLine("stuff")

23. Errors Runtime errors occur when something goes wrong while the program is running. //an out of bounds exception is thrown String s = "runtime_error"; Console.WriteLine( s[15] );