# Aliases of built-in types

# Built-In Types Table

The following table shows the keywords for built-in C# types, which are aliases of predefined types in the System namespaces.

C# Type .NET Framework Type
bool System.Boolean
byte System.Byte
sbyte System.SByte
char System.Char
decimal System.Decimal
double System.Double
float System.Single
int System.Int32
uint System.UInt32
long System.Int64
ulong System.UInt64
object System.Object
short System.Int16
ushort System.UInt16
string System.String

The C# type keywords and their aliases are interchangeable. For example, you can declare an integer variable by using either of the following declarations:

int number = 123;
System.Int32 number = 123;