The predefined types in C# have both value types and Reference types.
Value types have
Numeric Signed integer (sbyte, short, int, long) Unsigned integer (byte, ushort, uint, ulong) Real number (float, double, decimal) Logical (bool) Character (char)
Reference types have
String (string) Object (object)
Predefined types in C# alias .Net Framework types in the System namespace.
They are the same as shown in the following code
int i = 5; System.Int32 i = 5;
using System; class MainClass/* w w w. j av a 2 s .c o m*/ { public static void Main(string[] args) { int i = 7; // 0x7 bool b = true; // 0x1 char c = 'A'; // 0x41 float f = 0.5f; // uses IEEE floating-point encoding Console.WriteLine(i); Console.WriteLine(b); Console.WriteLine(c); Console.WriteLine(f); } }