Read-only properties C# with Example

Declaration 
A common misunderstanding, especially beginners, have is read-only property is the one marked with readonly 
keyword. That's not correct and in fact following is a compile time error: 
public readonly string SomeProp { get; set; } 
A property is read-only when it only has a getter. 
public string SomeProp { get; } 
Using read-only properties to create immutable classes 
public Address 
{ 
public string ZipCode { get; } 
public string City { get; } 
public string StreetAddress { get; } 
public Address( 
string zipCode, 
string city, 
string streetAddress) 
{ 
if (zipCode == null) 
throw new ArgumentNullException(nameof(zipCode)); 
if (city == null) 
throw new ArgumentNullException(nameof(city)); 
if (streetAddress == null) 
throw new ArgumentNullException(nameof(streetAddress)); 
ZipCode = zipCode; 
City = city; 
StreetAddress = streetAddress; 
} 
}