QuestionWhich of the following is not a valid variable name declaration?
Select one:
a. int 3a:
b. int A3:
c. None of the mentioned
d. Int a3:
Studdy Solution
STEP 1
What is this asking?
Which of these ways of creating a variable is wrong?
Watch out!
Variable naming rules can be tricky!
Remember the rules about numbers and capitalization.
STEP 2
1. Check `3a`
2. Check `A3`
3. Check `a3`
4. Check `Int a3`
STEP 3
Can we start a variable name with a number?
Absolutely not!
It's a big no-no.
Variable names *must* begin with a letter or an underscore.
So `3a` is **definitely wrong**.
STEP 4
`A3` starts with a letter, the letter "A", which is perfectly fine.
It then has a number, the number **3**, which is also allowed as long as it's not at the beginning.
So `A3` is a **perfectly valid** variable name.
STEP 5
Just like `A3`, `a3` starts with a letter (lowercase "a" this time) and then has a number.
This follows the rules, so `a3` is **also valid**.
STEP 6
Now, this one is sneaky!
In many languages (like Java, C++, C#), `int` is the correct keyword for creating an integer variable.
However, the capitalization matters!
It should be lowercase `int`, not uppercase `Int`.
Because of this uppercase "I", `Int a3` is **invalid**.
STEP 7
Both `3a` and `Int a3` are not valid variable declarations.
Since the problem asks which is *not* valid, and we found two, we must select the option that reflects this.
Since there is no "a and d" option, and "None of the mentioned" would imply they *are* valid, we can conclude that the problem has an error.
The best we can do is select **a. int ** and **d.
Int a3**, and inform the teacher of the problem's error.
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