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C# Variables

A variable is a named storage place for a value in a C# program. Each variable has a type that states the kind of value it can hold.

Declare and print

The score variable holds a whole number. The print line shows the stored value.

using System;

class Program
{
    static void Main(string[] args)
    {
        int score = 90;
        Console.WriteLine(score);
    }
}

A text variable

The name variable holds text in double quotes. The print line shows the text.

using System;

class Program
{
    static void Main(string[] args)
    {
        string name = "Hana";
        Console.WriteLine(name);
    }
}

Change the value

The level variable first holds 1. A new value then replaces the old one.

using System;

class Program
{
    static void Main(string[] args)
    {
        int level = 1;
        Console.WriteLine(level);
        level = 2;
        Console.WriteLine(level);
    }
}

Join values in print

The plus sign joins text and values into one line. The line prints as one piece of text.

using System;

class Program
{
    static void Main(string[] args)
    {
        string name = "Hana";
        int level = 3;
        Console.WriteLine(name + " is at level " + level);
    }
}

Example

using System;

class Program
{
    static void Main(string[] args)
    {
        string student = "Mina";
        int grade = 9;
        Console.WriteLine("Student: " + student);
        Console.WriteLine("Grade: " + grade);
    }
}

Key points

  • A declaration writes a type, then a name, then a value.
  • The equals sign stores the value in the variable.
  • A stored value can change to a new value of the same type.
  • A printed variable prints its current value.
  • The const keyword marks a value that cannot change.
  • Text joins with the plus sign inside a print line.

In this example, the first line prints the label Student with the name Mina. The second line prints the label Grade with the number 9. Each line joins a label and a value with the plus sign.

Note

A variable name starts with a letter in the programs in this course.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Programiz C# Compiler

Exercise

What does the line int count = 5; do?