Reserved Keywords: List of Key Terms in IT
Understand what keywords are in programming languages. Learn why you can't use them as variable names and see lists for C++, Java, and Python.
Reserved Keywords
Every programming language has its own "dictionary" of words that have special meaning to the compiler or interpreter. These are the foundations of syntax that you cannot use to name your own variables, functions, or classes. It's like trying to name your child "Bus Stop" – in everyday language, that word is already taken by the transportation system.
Keyword
Why are they reserved?
The compiler needs to know when you are starting a loop or declaring a function. If you named a variable if, the program wouldn't know if you wanted to check a condition or get a value from the variable. This would cause chaos and syntax errors.
Comparison of Keywords in Popular Languages
While many languages (like C, C++, and Java) share similar keywords, each has unique terms.
| Cecha | Language | Typical Keywords |
|---|---|---|
| C / C++ | int, double, static, volatile, struct | 32 (C) / 90+ (C++) |
| Java | extends, implements, interface, final | approx. 50 |
| Python | def, lambda, None, pass, with | approx. 35 |
Common Mistakes and Pitfalls
Variable Naming
Case Sensitivity
Examples of Keywords in Action
See how the same keywords build logic in different technologies:
int main() {
for(int i=0; i<10; i++) {
if(i % 2 == 0) continue;
return 0;
}
}Pro Tips
Syntax Highlighting
Identifier Naming Checklist
How to create names safely?
0/4Quiz: Check Your Knowledge
Which of the following words is a reserved keyword in Python?
Code Analysis Process (Mermaid)
What Next?
- Learn naming conventions like camelCase or snake_case.
- Check the reserved words list in SQL – they differ from general-purpose languages.
- Explore contextual keywords (e.g., var in C#) which are only critical in specific places.
- Review INF.04 exam materials to ensure you know the syntax of required languages.
- Try writing a script that checks if a given string is a keyword.
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