new variable using in unity code example

Example 1: how to add a variable in unity c#

void variable = 
private void variable =
public void variable =

Example 2: how to make a variable unity

public GameObject objectName; //creates a gameobject with the name "objectName"
private float myDecimal = 0.25f; //creates a float with the name "myDecimal";
//note that decimal floats have to end with 'f' and floats can be any numerical value.