Answer:
a) Variable-A variable is a symbolic name (or reference to) data. The name of the variable reflects what data the variable includes.It's purpose is to saving a data on particular point,it is a name of the address we want to operate.
Example-a,a1,a23,abc,abh_tr etc.
It should start with the characters, it may include numbers but not in starting and also the underscore at the starting.
b)Constant-A Constant is a value that we can't change, we stores it like a variable.The significance of constant : it's just a poor style to change the velocity of light, the value of pi, and other things like that. if we assumes some value it may produce an error, so making them constants is a type of defensive programming.
Example- pi=3.14 etc.
c) Assignment Initialization-The process of assigning a specific value to a variable at any point in a program or code because of the program logic requirement is known as an assignment operation.
Initialization-Defines and gives an original value in the same declaration to a stated variable.
Example int x = 7;
In this we can initialize the type of variable like - integer,floating etc.
We can declare the variable value in the same line.So,it helps in removing lines and saves time.