C++ Keywords (original) (raw)

Last Updated : 25 Apr, 2026

Keywords are the reserved words that have special meanings. Since their meanings are predefined, we cannot redefine them or use them for a different purpose.

C++ `

#include using namespace std;

// 'int' is a keyword int main() {

// 'int' is a keyword 
int age = 20;

// 'if' is a keyword
if (age > 18) { 
    cout << "Adult";
}

// 'return' is a keyword 
return 0;       

}

`

How to Identify C++ Keywords

1. **Syntax Highlighting: Most modern IDEs (like Visual Studio, CLion, Code::Blocks) highlight keywords in a different color. This makes them stand out from variables or function names.
2. **Compiler Errors: If you mistakenly use a keyword as a variable name, your code won’t compile. **Example: C++ `

int return = 10; // Error: 'return' is reserved

`

Categorization of C++ Keywords

To make them easier to understand, let’s group C++ keywords by context:

**Note: The number of keywords C++ has evolved over time as new features were added to the language. **For example, C++ 98 had 63 keywords, C++ 11 had 84 keywords.

Keywords vs Identifiers

So, there are some properties of keywords that distinguish keywords from identifiers. They are listed in the below table