C#: Variables Cheat Sheet

Integral types	sbyte, byte, short, ushort, int, uint, long, ulong, and char
Floating point types	float and double
Decimal types	decimal
Boolean types	true or false values, as assigned
Nullable types	Nullable data types

Defining

<data_type> <variable_list>;

Some valid variable

int i, j, k;
char c, ch;
float f, salary;
double d;

Initializing

variable_name = value;

Example

using System;
namespace VariableDefinition {
   class Program {
      static void Main(string[] args) {
         short a;
         int b ;
         double c;
         /* actual initialization */
         a = 10;
         b = 20;
         c = a + b;
         Console.WriteLine("a = {0}, b = {1}, c = {2}", a, b, c);
         Console.ReadLine();
      }
   }
}

=> output

a = 10, b = 20, c = 30