Question

Which of the following are valid variable names? If they are not valid names, briefly explain why.
4
4a
a4
did do
do
dodo
desire2Learn
DESIRE2LEARN
one-Hundred
One_Hundred

Create a program: to display the minimum value that can be assigned to each integer data type. You should be able to guess the names of these variable;
to modify the program so that aBoolean primitive data type has a different value;
to modify the program so that the char primitive data type outputs a lowercase letter and the statement reflects this.
Just show me the code of the program.

Answer 1

Generally, dashes and spaces can't be used because they mean other things. Similarly, variable names usually cannot start with numbers. So this excludes these 4.

4
4a
did do
one-Hundred

Answer 2

Valid Variable Names:
4a
a4
do
dodo
desire2Learn
DESIRE2LEARN
One_Hundred

Invalid variable Names:
4
4a
did do
one-Hundred

Reason:
* Variable name should start with any character or underscore (_)
* It should not start with number
* special characters are not allowed anywhere in the variable name except underscore(_) & dot(.)
* white spaces are not allowed in variable name

In the four invalid variable mentioned by me are invalid because:
4 : starting with a digit
4a : starting with a digit
did do: white spaces are not allowed
one-Hundred : speccial characters are not allowed ( '-' is used here)