# 2.2.3 Default Values with a Prototype

Recall that a prototype is an advanced declaration of a function. You saw earlier that prototype needs to have the same function header. While that is still true, the one clarification to that is that ***you only define default values in the prototype***.

```
// Define the default value here
double pow(double base, int exp = 2);

int main() { // Some code }

// Do not define the default value here
double pow(double base, int exp){
        // Some Code
}
```

The function definition still needs to have the same parameters and the same order, but you do not list the default value a second time.

### [Try This Example](https://replit.com/@Poston/223-Default-Values-with-Prototype#main.cpp)