1.2: Data Types Table
In this module we'll study types and look at some types challenges.
Types Within C#
Take some time to read through the table below. You can use it as a reference in the future. If it helps you learn, feel free to type the code in each of the rows:
Type
Description
int i = 0;
An int is a whole number with a size of 32 bits and range from -2,147,483,648 to 2,147,483,647..
short sh = 32767;
A short is a whole number with size 16 bits and range from -32,768 to 32,767. In the expression we assign sh to 32767. What happens if it is 32768.
byte by = 255;
A whole number with size of 8 bits and range from 0 to 255. In the expression we assign by to 255.
string s = "hey!";
A collection of characters with a size of up to 2 gigs or 2^32 bytes, or Int32.MaxValue. In the expression we assign s to hey!
char c = 'i';
A single character with a size of 16 bits. A string is just a linked list of chars. In the expression we assign c to the letter i.
var s2 = @"a \tree";
The @ symbol is used when about to call a reference tree as to specify a directory file on your machine such as \DotNetPreWork\HelloWorld.
bool b = false;
A boolean is a true or false statement. In the expression we assign b to false.
long l = 7;
Long is an integer data type that can just hold more than a normal int type. Exactly 2 times more. The size is 64 bit and the range is -9223372036854775808 to 9223372036854775808. Another way to assign this type is Int64.
decimal p = 99.99999999999999999999999999;
A numeral that can go to a 128-bit precision decimal with a range of 28-29 decimal places. A very costly data type that takes a lot of energy for the program to run. A decimal data type is often used to represent money or other data that needs to be exact.
double d = 7.80000000000000;
A numeral that has a 15-16 digit precision with a 64-bit size.
float f = 10.8f;
Floating point integer, must put f explicit conversion afterwards. Float is similar to a double only it is stored as 32 bits within the memory.
decimal dd = 7.80m;
Without the suffix m, the number is treated as a double and generates a compiler error.
int? ni = null;
When there is a ? afterwards it means the value can be null. Null means it can either have a value there or it can be empty. Null can be used when you are not sure if there will be a value or not such as with web services or database results. Use .HasValue to see if the current Nullable object has a valid value of its underlying type.
Challenges
Use what we've learned so far to complete the challenges:
File Location
Right click on the solution you made in the first module, go to Add > New Project
Select Console App (.NET Framework)
Name it
0.02_Types_ChallengesWrite your code for this module within
Program.csof that project
Important Note: Now that you have more than one project within your solution, you will need to specify which project will run when you click start or press CTRL F5. 1. In the Solution Explorer right click on the project you are working on 2. Select Set as Startup Project
Bronze
Create a list of value types: int, string, bool, float, double, decimal
Do two examples for each type
One is a declaration only
The other is a declaration with initializer
Print some of the values in the console
Silver
Use two different types to concatenate a single string, any string will do
Hint: The
+operator can be used with strings
Gold
Declare the year you were born as a string using a birth year variable with string interpolation.
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