C++ Default Args

What Are Default Arguments in C++?

Default arguments in C++ allow you to set default values for function parameters. If the caller doesn’t provide a value for a parameter, the function uses the default.

It’s like saying: “If nobody tells me what to use, I’ll use this value instead!” 😄

📘 Syntax of Default Arguments

return_type function_name(type param1, type param2 = default_value);

Let’s see how it works with an example!

🧪 Example: Function with One Default Argument

#include <iostream>
using namespace std;

void greet(string name = "Guest") {
    cout << "Hello, " << name << "!" << endl;
}

int main() {
    greet();           // Will use default argument
    greet("Alice");    // Will use provided argument
    return 0;
}
  

🧪 Example: Multiple Default Arguments

You can also set defaults for multiple parameters, but they must go from right to left!

#include <iostream>
using namespace std;

void showInfo(string name, int age = 18, string city = "Unknown") {
    cout << "Name: " << name << ", Age: " << age << ", City: " << city << endl;
}

int main() {
    showInfo("Max");
    showInfo("Lily", 22);
    showInfo("Jake", 30, "New York");
    return 0;
}
  

⚠️ Rules to Remember

• Default values must be provided from right to left.
• You can skip some arguments, but not the ones in between.
• Default arguments are usually declared in the function declaration.

✅ Summary

• Default arguments make your functions more flexible and easier to call.
• If a caller skips a parameter, the default value is used.
• Useful for setting optional behavior!

Try using default arguments to write smarter, cleaner, and more convenient functions! 💡