C#. last minute prep

Question 1

How to convert character/string to upper/lowercase?

Answer 1

string one = “Hi”;
string oneUpper = one.ToUpper();

char two= “h”;
char twoUpper = Char.ToUpper(two);

Question 2

What does .ToUpper() do for numbers?

Answer 2

It just returns the number on its own, does not produce an errror.

Question 3

How to check if a character is upper/lowercase, or a digit?

Answer 3

char two= “H”;
Char.IsUpper(two); //true

int three = 9;
Char.IsDigit(three) //true

Question 4

Math operators and rules for truncating, power, and rounding (to a select D.P.) on int num;

Answer 4

double num = 3.1415;

double power = Math.Pow(2,4);
double truncate = Math.Truncate(num);
double rounded = Math.Round(num, 2);

must always work in doubles.

Question 5

String handling, how to do:
- Index of a character (and if it isn’t present)
- Last index of a character (and if it isn’t present)
- Make a substring

Answer 5

string EmailPosition = “faisal@lgs.slough.sch.uk”;
int PosOfAtSign = EmailPosition.IndexOf(“@”);

int PosOfL = EmailPosition.LastIndexOf(“l”);
Console.WriteLine(PosOfL);

string hi= “Berub”;
string hi1 = hi.Substring(0, hi.Length);
//(start index, num of characters)

Question 6

Appending strings

Answer 6

string text = “”;
text += “A”;
text += “3”;

Question 7

How to convert from CHAR to ASCII code, and ASCII code to CHAR?

Answer 7

ASCII code TO INT:
char ascii = ‘A’;
int number = (int)ascii;

ASCII code to character:
int code = 66;
char ascii = (char)code ;

Question 8

Convert from F/D to INT, and STRING to F/D

Answer 8

int number = (int)double ; //truncates

double = double.Parse(string);

Question 9

List functions:
- Convert from string to list of characters
- Insert value at specific index
- Index of a value
- Remove a value
- Remove the item at a specific index
- Sort into alphabetic order A -> Z
- Reserve order of list

Answer 9

List<char> letters = string.ToList();</char>

letters.Insert(3, ‘A’)

letters.IndexOf(‘A’) //first instance, or -1

letters.Remove(‘A’) //remove first instance

letters.RemoveAt(2)

letters.Clear() //empty list

letters.Sort() //alphabetic order

letters.Reverse() //reverses order