data-type var1, var2, ……….. , varn;
 
where a data-type is an already-defined data type, while var1, var2, …. , varn are the names of variables. Note that, the variable names must be separated by commas, and the declaration statement must end with a semicolon. 

Example of Variable declaration:

1. int no;
2. int sum, avg;
3. float interest, amount;
4. char x,y,z;
5. float x, y; 
6. double a;

It is also possible to add modifiers with the basic data types during declaration of variables.
 
Example:

1. short int no;
2. unsigned int sum, avg;
3. long int interest, amount;