The data types that are predefined and are supported by programming language are known as **primitive data types**. For example, the primitive data types for the C++ language are as follows:
* `bool`
* `short int`
* `int`
* `long`
* `float`
* `double`
* `char`


## `const` primitive data type parameters 

Primitive data type parameters can be declared constant.
## Syntax
```
int sum(const int a, const int b)
```
The following sample code shows the `const` datatype parameters:


#include <iostream>
using namespace std;
int sum(const int a, const int b)
{
  return a+b;
}
int increment(int a){
  return ++a;
}
//int incrementconst(const int a){
//  return ++a;
//}
int main() {
  int a =10;
  int b=20;
  cout << "Sum is "<<sum(a,b)<<'\n';
  cout<< "Increment is "<<increment(a);
  //cout<< "Constant patrameters increment is "<<incrementconst(a);
  return 0;
}

## `const` data type use case
 
If we want to modify the parameter's value, then it should not be constant.
This is because when we write a parameter with the `const` keyword, there will be an error while modifying the parameter.  

In the above code, we use a non-`const` parameter that can be modified easily. However, if we use `const` parameters, the compiler will give an error.

> **Note**: We can uncomment lines 10, 11, 12, and 18 to check the type of error we get when modifying a constant variable.

What are const primitive data type parameters in C++?

Primitive data types in C++ can be declared as constant using the const keyword, preventing modification.

What are const primitive data type parameters in C++?

Primitive data type

const primitive data type parameters

Syntax

const data type use case

`const` primitive data type parameters

`const` data type use case