Guide to the Language

 StringBuilder Class
StringBuilder is a mutable string class. Because of the performance cost 
associated with replacing a string, the StringBuilder class is a better 
alternative when a string needs to be modified many times.
System.Text.StringBuilder sb = new
System.Text.StringBuilder("Hello");
The class has several methods that can be used to manipulate the 
actual content of a string, such as Append, Remove, and Insert.
sb.Append(" World"); // Hello World
sb.Remove(0, 5); // World
sb.Insert(0, "Bye"); // Bye World
To convert a StringBuilder object back into a regular string, you use 
the ToString method.
string s = sb.ToString(); // Bye World
CHApter 5 StriNgS

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© Mikael Olsson 2020 
M. Olsson, C# 8 Quick Syntax Reference, 
https://doi.org/10.1007/978-1-4842-5577-3_6
CHAPTER 6
Arrays
An array is a data structure used for storing a collection of values that all 
have the same data type.
 Array Declaration
To declare an array, a set of square brackets is appended to the data type 
that the array will contain, followed by the array’s name. An array can be 
declared with any data type and all of its elements will then be of that type.
int[] x; // integer array
 Array Allocation
The array is allocated with the new keyword, followed again by the data 
type and a set of square brackets containing the length of the array. This is 
the fixed number of elements that the array can contain. Once the array is 
created, the elements will automatically be assigned to the default value 
for that data type, in this case, zero.
int[] x = new int[3];

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 Array Assignment
To fill the array elements, they can be referenced one at a time and then 
assigned values. An array element is referenced by placing the element’s 
index inside square brackets. Notice that the index for the first element 
starts with zero.
x[0] = 1;
x[1] = 2;
x[2] = 3;
Alternatively, the values can be assigned all at once by using a curly 
bracket notation. The new keyword and data type may optionally be left out 
if the array is declared at the same time.
int[] y = new int[] { 1, 2, 3 };
int[] z = { 1, 2, 3 };
 Array Access
Once the array elements are initialized, they can be accessed by 
referencing the elements’ indexes inside the square brackets.
System.Console.Write(x[0] + x[1] + x[2]); // "6"